The Physics of Confections, Cotton Candy, Soft Cookies, & Brittle Crackers by Dr. Ted Labuza

The Physics of Confections, Cotton Candy, Soft Cookies, & Brittle Crackers by Dr. Ted Labuza


I cafe scientifique is a monthly series of
expert-led discussions on science and culture presented by the bell museum of
natural history for more information about the bell museum or to find out
about upcoming cafe scientifique programs visit bellmuseum.org or find
us on facebook and twitter Okay good evening and welcome to café
scientifique yeah all right cafe scientifique is brought to you by the
bell museum of natural history and yeah all right! oh this good group tonight hey
thank you all for coming out tonight on another Super Tuesday it’s awesome and I
hope everybody notices that i’m wearing my Bernie Sanders here tonight okay I am
going to turn it over to Leah now to introduce our speaker yeah. Thank you
thanks Kevin as always for a very energetic opening to the show I just
wanna say thanks to everybody here at bryant lake bowl and of course did you
ask this who sponsors the cafe scientifique who knows excellent yep the
Bell Museum so we’re very happy to be here tonight to present our speaker we
wanted to do some food programming for cafe scientifique and dr. la Busa here
wrote us an email reply to an email invitation to submit some ideas for
programming and he had such a range of topics that he could speak on just and
you might talk about some of them tonight but there were so many
interesting ones but one of the talks was titled the physics of confections
and I just thought that that sounded like a real treat no pun intended for
all of us here tonight so he may mention though that this talk also comes out of
science that was done by his sons and daughter two sons and daughter in high
school elementary school okay and and so there’s a paper authored by
you proudly has told me by Labuza Labuza and Labuza out there
floating around in the world my people find it on the internet um but I would
love to just hand the mic over to dr. Ted la Busa let him get started with the
presentation thank you. help me I want you to pour these ice
cubes into here and put two or three in each of these so what we have here is a
little experiment we have a paper plate and aluminum pie plan and we have my
magic melting table you got to put on this on this one also and i have i have
three people whose the the paper one so you’re going to be it you watch these
look at the time now and tell me when they all melt you’re going to be there
and you’re going to do that for these and then it’s already melting how about
you you’re going to watch this so it’s already we started two minutes and just
shout out when it’s all melted shout out the time and we’ll talk about it at the
end why this has occurred okay so I’m going to talk about various things I
just wanted to also say a little bit about some new technologies that we have
before we get into candy how many have heard about ultra high pressure
processing a couple of you okay starbucks just bought about six months
ago they bought this company here its juices that are pasteurized but without
heat and I think there are about seven eight dollars a bottle not not cheap
hormel the former director research this PhD on this process for me and they’re
so I’ve been involved with it so think about this you take this room here and
we got a basement below and we put vertically a
gunbarrel from a battleship so 20 centimeters thick walls vertical the
bottom is sealed and we put food in packages which we vacuum pack so there’s
no air in it so like deli meat or this plastic bag you can’t put in the bottle
or can and we put it in through baskets and lower it down into this one and a
half storey coil battleship barrel we fill it with water we seal it it’s
hooked up to a pump that’s called an intensifier pump in the bottom basement
when it’s running nobody can be in a room so there’s motion and a vision
detectors to make sure people are not in a room and it pressurizes that barrel to
99 999 thousand feet okay the depth three times the depth of the Marianas
Trench okay and what it does is it kills the microorganisms that are in the food
it doesn’t affect the texture of the food at all the food tastes like fresh
orange juice or whatever it is like that and why it worked and maybe you can hold
the microphone for me for a second water molecule has an oxygen and it has two
hydrogen’s there are about 104 degrees C apart and then under that water is an
interesting thing because it forms a cloud around nucleic acids like the DNA
of the organism forms a cloud around proteins that helps stabilize the
structure because there are large polymers and that cloud is based on
interactions between water and the protein with its structure well under
that high pressure you actually squeeze the model feel like this and that
disrupts the structure the nucleic acid and the microorganisms die but the
proteins they don’t get affected so that they come out just
I originally actually one of the first processes that was done was for what’s
the most dangerous food that you can eat that’s up on the top of the list okay
you heard me talk yesterday about that yeah yeah I agree I agree yeah raw milk
is… “oysters” is the top one but but actually it’s it’s both osters and and
raw milk I would put in the same category very very dangerous food well
you can pasteurize with high pressure and there’s about six companies in
Louisiana that do high pressure processing of oysters and they taste and
have the texture of a fresh pic oyster but there’s no organisms in it and
they’re the only or they’re the only oysters that are now allowed to be
served in California because of the danger of it so very very interesting
thing so seven minutes 23 okay we still got ice there I gotta take this off here
um so let’s get to the topic oh i should say one other thing another way to do it
i just forgot that has anybody bought these these are pasteurized eggs in a
shout okay okay and it says safe for any recipes how would you be able to
pasteurize egg in a shell could you do that in a high-pressure processor no
because there’s an air cell in an eight and it would crush the egg this goes
back to the old days of pasteurization low temperature long time and if you do
it at the right temperature about 54 degrees c and for 55 minutes you can
make these safe for any recipe the big market for this is for people like me
who are over 70 that if you’re in a nursing home or in hospital and you want
a sunny-side-up egg when you crack this egg open
it looks like a raw eighth and so you can make this any side that it’s there’s
no white that’s coagulated or anything like that so that low temperature allows
the organism to get killed but the protein to not get denatured in there
which is interesting 726 and you had Oh over there so is though that was pretty
close all right this is still there all right so we’re going to talk about candy
these two people here change the world in some way which we’ll talk about in
terms of what we going to do so I’m going to talk about some of the science
I did before I met them and they did something they were hairy was a chemical
engineer in polymer science from rpi Rensselaer Polytechnic general foods
which is doesn’t exist anymore and his living partner Louie Slade was a PhD in
chemistry and they worked at the tarrytown Research Center in New York
and i’ll talk about what they what they did so if we take a food high moisture
solution elastic jello like it would be some fruit or whether or a colloidal
dispersion or a cell trap structure like a banana or whatever and we dry it and
physicists are now beginning to work in this area but they’re embarrassed by
saying that they work on food so they’ve termed something called soft condensed
matter and there’s a journal of soft condensed
matter and I I kept that argue with him well you know hard-boiled candy is not
soft you know so we got to have also not so soft condensed matter as well so if
we dry it down to a semi moist state and I’ll talk about what that means or low
moisture state the because we take the waterway usually rapidly we end up what
we call is amorphous structure that’s a physical term but let me talk about what
it it could be two states it can be glassy state so you make a potato you
take a potato chip put in a fryer take a piece of potato for the new provider
hold it for the right amount of time take it out it’s crispy it’s brittle or
if we don’t bring it down so much like making a caramel candy it’s rubbery so
we can have two different states with pretty much the same type of materials
that are going into it and we can go back and forth we can take a glassy
material make it rubbery like a potato chip and then dry it back down again and
we can make it brittle so we can go back and forth and if it’s in this rubbery
ductile state if we store it at certain conditions and it’s got sugar in it then
we have the sugar crystallizing and it causes some problems and we’re going to
talk about that as we go along so let me let me talk about a concept that didn’t
exist before the 1950s that’s the concept of water activity it’s something
that we teach our students I was in groups that were around the world that
were the first to come up with this principle so let me take this very
simple thing a you’ve seen these packages right in vending machines
cheese-and-cracker that one a very negative environmental award for they
said why don’t you put the cheese on the cracker
and you won’t have as much packaging in there and you wouldn’t have to put that
little paddle so you could spoon it okay oh good good question why not okay so
let’s say why not so usually this I shouldn’t call this cheese is a fake
thing that looks like cheez-its we we call it rubbery or ductile if the
mechanical engineers call it ductile material that can flow if you force it
through it’s usually about ten to forty five percent water depending on how
creamy you want it so it’s in this side and on this side we have the crackers
and they are brittle you take them hear that sound you could put that back
together by gluing it if you got all the pieces yay part of it already okay
that’s all right we’ll forgive you so this is usually two to five percent
moisture notice ten to forty five percent if I put them together what’s
the moisture going to do right so it goes from one from the high moisture to
the low moisture and what’s going to happen in the end if we left it a long
time soggy cracker but about moisture content did you end up the same moisture
huh wow this is going to go down and this is going to go up okay and that’s
that’s a good question you know what’s going to happen in there so here we put
the cracker let’s say I took the cracker and I put it in a environment at
seventy-five percent relative humidity at 25 degrees c and i measured its
moisture change let’s say for three percent and eventually it equilibrate
sout at fifteen percent and I take those crackers put a hundred grams put it into
a jar mason jar whatever really tighten so that it’s not going to be affected
any more and then I do my second experiment
where I put the cheese at the same relative humidity and temperature and
it’s going to lose moisture let’s say from forty five percent down to
twenty-five percent and again I seal it up okay and now I do my third experiment
so I have a hundred grams of cheese here at twenty-five percent moisture and 15 a
hundred grams of cracker at fifteen percent moisture and I’m going to take
the jars take the duct tape off put them together put a duct tape around and wait
for maybe two months to see what happens so the moisture is going to move from
here to here right right so will they equilibrate the twenty percent moisture
why not right for more well maybe you’ve got something but there’s there’s a
physical chemical property that is never taught anywhere except in food science
programs okay and it comes from this equation I’m not going to show you many
more equations okay i just want to point out there is an equation for this that
says the energy state of a molecule in a year in the vapor state or in the liquid
state is equal to the energy of the pure substance plus a gas constant times the
temperature in kelvin times the natural log which you know you don’t have to
worry about with all this shit means of the activity of the set of the species
and the activity is a physical chemical term and for liquids that evaporate that
activity is related to the vapor pressure that the water would have in a
given system / the vapor pressure of pure water very very simple thing we
call that the activity of the species in water we call that a which is small
capital not small capital L a small a with a subscript w and it’s called water
activity or we call it a sub W I have a license plate on one of my cars is a sub
W okay I’m crazy so we have cracker 100
grams 15 grams of water 85 grams of solids cheese 100 grams 25 grams of
water 75 grand in solids and we total up 200 grams 40 grams of water 160 grams of
solid so if we take the average moisture the mixture its twenty percent so if i
was working somewhere i would send it up to my analytical lab they would first
grind the whole thing up and say yeah its twenty percent moisture yeah it’s
true but then I said wait a minute i sat in some stupid seminar by some guy who
says no there’s something about thermodynamics that’s involved in here
okay and what the thermodynamics says is that what the equilibrium is is that the
water in each different domain the cracker the cheese and the air are all
the same so they all come to the same water activity so if we look at this
here’s the cheese here it’s going to lose water the cracker is going to gain
water and they’re going to come to an equilibrium water activity now who cares
this is a this is a huge business that is a real problem for the food industry
I would like to make a sandwich that last long my bread has a water activity
of point eight my meat as a water activity of point nine eight and so the
bread get soggy so I’ve got to figure out some way to slow that down or
prevent it there’s this research has been going on for twenty years to try to
find a nice simple solution good example here a crispy cone three percent
moisture its water activity I always didn’t show up on here its water
activities about point two five I put fill it with ice cream this is a frozen
novelty only have you ever bought frozen cone so the water activity ice cream at
that temperature the freezer is about point eight five
so the ice cream is going to have moisture transfer into the crack into
the cone what’s going to happen to the cone so it’s going to become an Ice
Cream Sandwich know that we like ice cream sandwiches but we want to crispy
cone so how do you solve this eat it quick well it’s gonna it the problem is
that it’s going to occur before you get to the house with it okay that’s a
problem huh make the contrary you can’t make it much drier we’ll see them ah
what a seamless between ice cream at the corner but if you between the ice cream
in the car so what what do you put in chocolate chocolate yeah that’s what
they eventually figured out what to do chocolate is about fifty percent by fat
you’ve already heard about chocolate in there at that temperature it’s going to
be a solid crystalline form and it is a very very good barrier one of my
students actually measured this and it’s equivalent to the water vapor
transmission you know those big black bags that you use for in the one and
four garbage cans stuff like that that’s six mil six thousands of an inch thick
polyethylene it’s a very good barrier so the chocolate works okay am I going to
put you up late in a beef and sandwich thing you know no am I gonna put that in
there you know maybe but you know it’s going to work but you know more calories
and that’s that’s our real problem is the more calories that is going to occur
in there so if we take take and plot the water activity and goes from 0 to 1 and
water activity is essentially the relative humidity that the food has and
let me just show you here here’s a little water activity meter it’s made by
the Germans it’s got a gauge in here that has relative humidity so I put a trail mix in here that I’ve
made just recently and it’s equilibrate ‘add I can’t show it to you but I’d want
to fall all over the place but it says that the water activity in there there
was a lot of fruit and a little bit of peanuts and the water activity is about
point six eight ok so the nuts picked up moisture from the raisins and stuff like
that smells bad right sit yeah be the nuts picked up moisture and that
moisture caused the nuts to go go rancid faster and i’ll talk about this in a
couple of minutes and if we take one of the raisins Plus let’s not too bad it’s
uh it’s not as soft I made one with gummy bears put some gummy worms as well
in here so here’s a gummy worm that was in with the crackers you want to break
that in half yeah I gotta do read how would you how would you describe that
texture is a brutal really hard riddle glass yeah yeah okay yeah the polymer scientists call
that glassy okay and that there is a physical property that goes from the
glassy state for the rubbery state you’ve eaten potato chips yeah they’re
glassy or rubbery both yeah out in the picnic at seventy-five percent relative
limiting in one hour they’re soggy and so that we call that a rubbery state and
that’s what we’re going to talk about is that that interesting transfer what
happens in there so here’s 02 one that’s the water activities that be zero to one
hundred percent relative humidity and fruits vegetables meat stuff like that
have a water activity about point nine eight very high and they’re going to
transfer moisture very rapid into a dry system beef jerky somewhere in here less
than fifty percent moisture in a 1 gram for gram of Solace ratio water activity
around point eight has to be less than point eight from a legal standpoint so
that’s safe to eat dummies around point seven raisins rice and right here we got
two different states in there we got dry material the rye and the rice and we got
the raisins raisins 0.65 the cereals about point two five and so over time
moisture is going to transfer into the raisins now these were raisins I pull
this raisins I pulled out of a cereal box that I head around for six months can you bend that mystery is pretty huh
pretty tough yeah I did that before it gets brittle it gets tough leathery okay
we want some leather eNOS in beef Jerky’s but if it gets too leathery it’s
going to pull your teeth out okay lots of cereal companies have been sued by
people who have broken their teeth from eating raisins raisin bran cereals okay
so we can solve that problem and I’m not going to get into much detail we can
solve that problem by adding a different plasticizer that raisin behaves like a
polymer how many of you made like gallons of food then you put them into
Tupperware containers and put them in the freezer so you can have meals I
usually make two gallons of Italian sausage and you know my special recipe
and when you put the hot stuff into there that’s pretty soft right you can
see you can bend it stuff like that so you’re put in the freezer and if you’re
at three o’clock in the morning and decide you I’m going to go have
something I go out there I had a little too many beers that night and I take it
out of the freezer and I drop it that speak that plastic became brittle
because it was at cold temperatures and it will fracture and you now have big
holes where it broken off in there and that’s again a glass transition type of
phenomenon that occurs in there so what I’m not going to read through this list
but in our laboratory at MIT and then when i came here in 71 we came up with
all kinds of solutions to use of water activity term so for example we know
that if the food has a water activity less than point 6 no microorganisms can
grow in fact no micro organisms that are pathogens
can grow a water activity of 0.85 so are dry foods safe nope we’ve had outbreaks of
product with better dry foods like chocolate like peanuts like they’re all
below point A five some microorganisms like Salmonella can resist dehydration
and say they go into hibernation and when you eat them again and you know the
biggest peanut butter what’s the water activity of peanut butter? you’re pretty close it’s about point four or five okay it’s low it’s soft
because of the peanut fat and so it spreads nice and easily you put in
refrigerator doesn’t spread very well because the fact solidifies in there and
that peanut corporation of america case resulted in 350 food companies having to
withdraw a product because they didn’t do the right things that they should
have it korea actually was the grandfather of creating the new Food
Drug and Cosmetic Act called fisma food Modernization Act which I was very
involved with in there I am ha on a food safety committee for the food and drug
administration I was appointed last year by the Commissioner in there and so
we’ve been we’ve been very worried about that we’re looking for ways to
inactivate in a dry state that high pressure battleship barrel is not going
to work and low temperature long time microorganisms in a dry state have much
higher resistance to heat and so we’re looking for other ways to do that so one
of the things I published which has been cited maybe over 5,000 times is this
stability map I published this in 1971 by 1971 we had figured out most of the
critical things of water activity in terms of food and in fact what
ben is that all of a sudden in the pharmaceutical area realized that was
important for them too this is one of the you know like canning was something that
we started they came into the pharmaceutical and his whole concept of
water activity became a very important thing so one of the critical issues
around that time is the law the change in textures acceptability of a product
and so 1981 one of my graduate students here at University of Minnesota
we publish a paper on water activity effects on sensory crispness so here’s a
measure of the hardness of the product as a function of water activity and what
we found is somewhere around point four and up two point five and this was this
happens to be four saltine crackers all of a sudden the hardness of the product
goes down significantly so we know water activities important but it doesn’t tell
us why in fact when I sent in that paper it was rejected because I didn’t say why
it occurred so I came up with a pack a little paragraph that I put in there I
said well the water bound with the starch and now when you bit on it the
water act as a lubricant and so the starch slid past each other and it
became softer they accepted that I have absolutely no proof for that happily no
proof so after that publication lots of papers
hundreds of papers people started working on this problem well around the
world there was a meeting which had 250 scientists in wagon in in netherlands on
crispness of food stuff like that and in 1990 88 and 89 those two people Slater
Levine that I showed you before they came up with this idea of the glass
transition phenomena that comes from chemical engineering in polymer science
there as I said I gave up boating my boat’s name was water activity to my
wife’s car is n TR o P an trophy and my other car is kinetic because I studied
kinetics of reactions I mean weird you know weird scientists and I gave up
fishing this is one this fish I actually caught by hand but we won’t go through
that story here okay so what we knew from water activity is that a water
increase change things across things have become sticky and caking you you
all have probably observed that if you left brown sugar and a can for a long
time all of a sudden you’ve got a brown brick in there that’s a kick taking
phenomena so that’s crystallization of sugars and starch bread staling getting
hard sitting out is a crystallization phenomena and so from polymer science
that says that as a function of percent solids you have this line that’s called
the glass transition line and I’m not going to go into how we determine that
it was a very very complex thing it’s called differential scanning calorimetry
below above the line the product is softer more flexible lower modulus of
energy sugar can crystallize fast reactions and below that its glassy so
we have a rubbery state here in the glassy state here what we know is if we
increase the temperature or by going in this direction or
increase the moisture by going this direction that there’s lines that
represent how soft the material can be and so the more were above the glass
line the softer it is because of the elastic modulus which comes from the
mechanical engineering of this so these are things we know where moisture game
becomes soggy potato chips cereals crackers extruded snacks like here’s an
extruded snack you’ve all seen these is this crisp someone but-but-but bite here
take a piece of white one oh sure some crispness delicious the more air that’s
phoned into a product the softer it becomes no because because it just
doesn’t have the solids that shows the brakeman so one of my former students
worked with my former PhD advisor said is that we can take a theoretical state
diagram where we have the boiling point line the freezing point line the
solubility line for if it’s sugars if it goes across that line it becomes
crystalline and we can put the TG line here and now we have a map that shows us
what’s rubbery and this little area here what is glassy it’s a very small area
that’s glassy so if I take a potato slice that’s at ninety eight ninety
ninety-five percent moisture and I put it in hot oil I’m going to boil it above
that line and then I cool it down and bring it to here so I go from a crisp
wet material because you bite on a potato slide that’s a different kind of
crispness than what is with the polymer thing that we’re talking about and
that’s that’s in this region here so I was looking for back in the early 90s
a way to try to come up with techniques for teaching our young scientists who
are on their way of how they could understand it from a very simple way so
I says I’m going to do it with my children so I started off with my son
tag he did crispness texture changes in brittle cookies basically like vanilla
wafers and chocolate wafers the stuff that you buy and use it for various
things this is the texture meter here he presented it at our national meeting of
my scientific society the first from work he did in 8th grade okay this is
before posters real posters if you’re those who have been in sight when you
had little sheets of everything and so he presented a National Museum in New
Orleans here’s the device so you mount it over we have different kinds of
mounts and things like that and then we bend it and we see how it cracks if it’s
brittle you get a straight line and then it breaks if it’s a material that yields
so it’s soft you’re going to have a line that’s linear here reaches a maximum and
then it’s so slowly decreases because it’s too wet so here’s seven percent
moisture 23 degrees it breaks 45 degrees so temperature and moisture content are
important in this if we store it at zero percent humidity for four weeks we get a
stress strain curve which shows it’s brittle it goes up to 25 Newton’s if we
store it at seventy-five percent relative humidity it goes up reaches a
peak at only one Newton and then it extends out and so we can very easily
have some mechanical properties that measure this and it becomes important
for doing that so that led to a PhD student of mine
funded by a number of cereal companies to come up with what is the key thing so
we did lots of more experiments different kinds of measurements of this
TG curve and a lot of sensory testing so this is sensory testing we train people
to evaluate crispness and you see up to about 30 degrees C its crisp and then
all of a sudden it becomes non crisp and what we found was that on that graph I
showed you before there was a line parallel to the TG line that said if you
went above that line you became non crisp and so this now helped the food
industry especially in the snack industry where crackers and stuff like
that to really do this a lot of people don’t know much about differential
scanning calorimetry so we do a lot of work for them in terms of doing this so
here’s his presentation again here’s a paper well actually there’s a book
chapter which he was a co-authoring and not only that but the triple-a s picked
20 students around the country that were in grade school to go to a forum in
Beijing China to present their poster there and he was one of them and in fact
one of his same kid in the same class I worked with him on ph effects on enamel
of teeth and he got to win too so we had two people from st. john the baptist
school in new brighton for this so to ensure good crispness you want to have
make sure that the glucose level is less than point five because sugars lower the
TG curve and that makes it more sin you want to have a thicker slice like they
do here longer deep fat fry so lower moisture content which is what somebody
said before that’s a good idea and then have a package that is a foil laminate
so it’s a very very good barrier to moisture pick up okay and so it’s more
expensive but it gives you the shelf life you want
so the second one was taking phenomena that I wanted to look at so I decided
well actually it came about my son middle son ordered some cotton candy
over the web okay when it reached our house and it was some summer about oh
now 15 years ago whatever we lifted up the bag there was big hard clumps in the
bottom it wasn’t cotton candy and so I says hey this is a good thing to look at
so we looked at cotton candy so when you make cotton candy you take crystal and
sucrose you raise the temperature above 210 in that row rotating cylinder that’s
in the center it melts spins it out as a liquid stream it produces a glassy
material if you take that material and we’ll look at it it’s not crystalline at
all it’s an amorphous material you catch it on a paper cone and if the humidity
is high it’s going to collapse and then it’ll recrystallize so it’ll go back to
the original state so this is just the the map that we show I talked about so
here’s the boiling point line the solubility or line for the sugar here’s
the rubbery state again a very small region here where you’re at room
temperature that it’s a glassy material and we worked with people at University
of Wisconsin to produce to this curve so here he is making cotton candy I made a
mistake the first time I did this okay it was a winter time we had to get
something going and I bought some of these cotton candy machines little ones
and we did it in the kitchen what’s the humidity inside your home during the
winter time low you know usually less than thirty percent okay so one is the
cotton candy didn’t stick that a cone but any other surface that was a little
bit cooler I hold the whole damn kitchen was now covered with cotton candy three
days to wash it off that was my penalty he also presented at the National I of T
so it was the second one doing that so here’s the experiment here’s the TG line
these are actually measured you get random because it’s all is a very
difficult thing to measure and we stored product at eleven thirty three
forty-five fifty and seventy five percent relative humidity in jars so it
made the content candy fill them up into a ball jar and went about it so my son
learn how to do x-ray crystallography the first time we went over there
there’s a sign no food allowed in the characterization facility this is no
we’re not going to eat it which is going to do x-ray crystallography and they
said what is hell are you doing you know so if you do a crystal you get in the
old days you get a pattern on a piece of film I mean I did work back in the 60s
on film now we have something that actually gives you something that looks
like a chromatographic you see this on CSI whether it’s a cocaine or heroin or
whatever type of thing for crystals so you get very distinct peaks at different
angles in there this is the instrument itself very easy the most damage you
could do is not close it and somehow earlier it goes on and now you still
start spilling x-rays all over the laboratory so they’re very keen on that
okay so here’s my initial cotton candy in a jar and here’s it being x-rayed and
you see this halo pattern very low counts spread out no peaks at all that
says there’s no crystals in that cotton candy at all this is sucrose crystal and
sucrose you see the very big difference in the patterns between them so we could
identify that in fact that the cotton candy was a mortal
and not not kristalyn thirty-three percent relative me about five percent
moisture at two days that full jar had now collapsed that collapse is due to
the fact that you have enough water that it breaks the bonds between the sucrose
molecules and the force of gravity pulls it down so it’s a effect of gravity
that’s causing it to flow in there at three days now this was hard as a brick
okay and it was crystalline in there here’s the x-ray diffraction results you
start seeing now all these Peaks for sucrose in there so you could see very
clearly that this occur this is at forty five percent and now had forty five
percent in in five hours you saw the same crystal and pattern at seventy-five
percent one hour so this summer when you go to state fair we’re Washington State
for error or whatever bike two counties eat one watch the other and taste the
other every now and then okay and what you’ll see is it’s going to collapse and
then it’s going to get grainy because you’re making sugar crystals in it and
that’s what happened with that stuff that came in there so this was a nice
way of explaining the whole glass transition effect of moisture on doing
something again the solution is good packaging and place do not place a
direct sunlight store it in the cool dry place and it applies to other things and
so and here’s my son at IFT this was my former visor and this is one of my
colleagues who worked with him on coming up with a state diagram so candy
thermometers grandma you all about glass transition you use that candy
thermometer and if you what you do is you take the sugar solution yup
Oh sugar solution yeah and bring it up to a certain temperature add more things
to it and then so you got a higher solids content and bring it up to the
boiling line and carry it up and then bring it down in temperature and so if
we want a caramel we stopped at about 248 Fahrenheit bring it down it brings it
into the rubbery state and its soft and put like taffy type of thing if we want
a hard ball we bring it down here and it’s in the glassy state or peanut
brittle it would be the same type of thing but you know it’s all on that
thing now what drove me here for a project for my daughter is we have a
farm in Northern California we were out there one summer when she was still in
grade school and it was about 115 degrees outside dry dry heat very very
hot we decided to take our car and go up to Lake Tahoe to swim I bought some
Altoids and out towards you used to be able to buy and I haven’t seen them a
long time or little hard balls in a metal metal ice can you remember that
type of thing and well we left them in the car and this was hard ball candies
and we came back it was left in the car and what do you see what does it feel
like is it soft Oh put put your hey whoa this is it’s like jelly it’s like jelly
I mean if you leave it sitting out in the air it’ll dry out and get very hard
what’s jelly so what happens to those hard boil candies melt it didn’t melt right its flow under
the force of gravity okay how many of you eat melted cheese sandwiches okay
cheese on a pizza or in a you know when you do it on a melted cheese sandwich
you got to change that to gravity force cheese sandwiches the the fat melts at
35 36 centigrade but that doesn’t make any softer it’s the protein that flows
protein can have that same property there which is a very interesting
property in their key of course and I put this up here just as an extra thing
is uh if you leave Carnes out in the Sun in there this group has done a lot of
work it was done here’s the pediatric Journal they showed it didn’t matter
what the color of the upholstery or the car was you got about a 40 to 50 degree
or the beginning temperature you got about 40 to 50 degree Fahrenheit
increase above the air temperature inside the car so a 60 degree car can go
to 110 in two hours at if it was 83 Fahrenheit takes 15 minutes to hit 109
and if you have a body temperature in a child that’s it hits 107 they die so
that’s a that has nothing to do with candy i guess but some science so here
we are the initial sugar solution is basically sucrose solution you bring it
up to boiling carried out and then bring it down in here and you’re now in this
region here so it’s a hard boil candy and both moisture increase moisture
temperature increase or temperature increase can’t cause it to change in
there and that’s that’s what we’re facing in this and this is what my
daughter did she basically made a scale here’s loose and drive he turned they
can over it drops out somewhat sticky at two very sticky but
will not fall out and then eventually flows together so that the structure is
gone completely and basically thats related to the glass transition line I
did I left that off just because we want to finish this whole thing I did write
them they didn’t have any warning letters on it and now they have on their
cans keep in a cool dry place and I also asked them because that’s the other
thing is that moisture chemical effect this is that they should put a rubber gasket casket in the lid type thing okay
you get five points in my class you get two dollars and as catherine says don’t
keep it in the car so my last thing soft cookies you make a soft cookie this
basically the chocolate chip type of cookie and if you leave it out even in a
sealed container in two or three days it becomes crumbly you know it’s not got
that nice soft especially if you go truck’ll chip cookie when it’s hot
coming out of the oven I love that okay so it goes from something that’s a soft
cookie to something that’s a hard aged cookie stuff like that it’s really firm
and crumbly it’s not it’s not crispy because the structure is different than
what we have in a potato chip type of thing back in nineteen fifty eight the
couple of companies came up with an idea of making a chocolate chip cookie that
hadn’t two layers there was an outer layer that was a dough with sucrose ok
and then inner layer a dough with high fructose corn syrup normally you would
have all sucrose high fructose corn syrup lowers the TG line so you can get
a more soft product so you have a soft outside
and you have a nice sort of hard outside very important because he would put a
bunch of soft cookies together and you put them through a distribution center
okay you’re going to end up with a mass of cookie that’s all stuck together okay
so that’s that’s what they did in this x-ray crystallography proved that type
of thing so here we’re doing that we’re making this rubbery that’s the inside of
it the problem is that when you’re in that rubbery range then sugar can
crystallize and have sugar crystallizes it acts as part of the plasticizer with
the water so you get less platter plasticity and so you get a more and
more harder cookie in there and then water that the sugar was reacting with
does not react with a crystal that water transfers into the starch granules and
so you even lose water at the same time so here’s a soft cookie at one hour no
peaks at all to a lame orifice within one day you start seeing sugar crystals
forming five days more and more ten days really significant amount you see the
crystals here in there they’re not connected together so it doesn’t form a
hard texture it’s just single crystals that are growing inside there and if you
measure the texture again like my son did here’s that one our way down here in
terms of grams force and in 21 days that’s about five times harder up there
it’s unacceptable hardness so you know too nice instruments to do this in there
and this is a study that we did for 21 shelf life this is the control so it
started up then slowed a little bit but then got harder again at 400 kilopascals
that’s the modulus of elastic modulus that cookie is unacceptable so you see
that you know in about six days it was unacceptable if you took sugar out
gets even worse see it’s up here there if you added some high fructose corn
syrup a friend of everybody of sugars you know that it works really well it
keeps it down here we didn’t carry it out longer than that because we were
just looking at bakery type stuff that you would buy from a local bakery in
there and then we looked at other combinations what we found is that we
could really slow down the crystallization of sugar by adding in
raffinose anybody know what raffinose is? Ever hear of that? that it’s a sucrose
molecule glucose fructose and it has and that’s in a plane and it has
attached to it a galactose molecule so it’s three moieties that are present in
there we can’t digest it it’s one of the main sugars in beans that creates a
problem of flatulence so we can call them flatulent cookies okay but but five
percent five percent raffinose significantly reduced the hardening of
this and that’s because what happens is the growing site of the crystals the
crystals may start but the growing side of the crystals are sucrose so the
Google is glucose glucose fructose that attaches onto that growing site but you
gotta galactose sticking up from that site and no more sugar can come down in
that I Harry so it slows down crystallization significantly so I’m not
going to go through all these mechanism so let me end with this when Slade in
laveen first got involved in this whole area they basically told us that water
activity was the useless term so we had a big battle in science we had a big
meeting in Nottingham in 1991 we’re actually both sides were throwing stuff
at each other and I says you know I suppose wait a minute you know
what our activity is really important chemical reactions because we know that
I published two hundred papers on things like that what glass transition does is
it tells us something very much about how to control problems with texture so
it’s a very important tool for the food scientists food technologists who’s
creating products itself so when they tour the short courts here I and I
invited them out to dinner at D’Amico cucina when it used to have the
restaurant on first street was the first read there yeah first avenue yeah and uh
you know nice so so we’re and put you know what candles on the table crystal
there my wife and I got there early and Harry and is what and his partner came
in and I got up to introduce them to my wife because they did not met her and as
clumsy as I am I knocked the table and a glass flipped over and wet hairy with
water and I says Harry that’s water activity so two years later I gave my
short cords to a group about 50 people in Sweden and uh a young lady came up to
me she says you know Harry really blew it he should have said no Ted that’s a
glass transition and with that I will end thank you very much all right I will
take questions from the audience I’d give raise your hand and I will get over
to you thank you for your talk is very informative um is the biggest factor in
cookie freshness or like palpability the sugar content that you mess with or
is it are there other factors that can also be easily controlled well the
biggest problem is textural changes yeah the people who have tried to do various
soft moist cookies for with six months shelf life the problem is the sugars
that you would add in I say high fructose corn syrup that would lower the
TG so it stays so after like I showed unfortunately they react with the
proteins present through something called the Maillard reaction that
produces darkening well if it’s a you know a chocolate chip cookie maybe
that’s not that bad but it also produces very bitter flavors and we don’t have a
good method to slow down the Maillard reaction so that’s one of the key problems
and now with everybody wanting clean labels you know you don’t want to see
sorbitol or mannitol or high-fructose corn syrup on the list and that’s that’s
a real problem so we’re we’re inhibited by the consumer concerns that are out
there and thank you again for your enlightenment what I’m wondering is the
radiation has been downplayed a lot because of
other hazards is this cannon method going to resolve what the radiation
can’t do is the cannon method cannon method is extremely expensive a single
unit is about three million dollars and it’s a batch process so it’s you put it
in there you hold it for 15 seconds and then you take it out so what hormel has
done is they’ve put in six of them so that they can run it you know with the
right time scale they can run it as almost a continuous process a radiation
has been around as a I went to MIT as an undergraduate in and I was in the
nuclear physics program because I when I was in high school I built a laboratory
in the basement my house and I synthesized six different explosives
okay today I would go to jail for that and I because my family didn’t have much
money I got a job in there cobalt-60 or radiation facility and I met some people
from the Army who were working with somebody in the food engineering program
and I got excited about that and the food engineering program gave me a
three-year scholarship so that’s how I went from nuclear physics into food
engineering in there and the problem with irradiation is cobalt 60 is a high
target for bio terrors you know that because you can blow up and then you can
spread radioactive material out there is a e-beam process that you turn a switch
on and off and so there’s no radioactivity and there’s a few things
around here but you are you say the word of radiation and to everybody that’s
anathema you know it’s a real problem you know so I I don’t see it as a
alternative and it’s it is used most of the spices that you have
because the way spices are handled in the Asian countries they have a high
chance for containing pathogens they’re sent the spices have sent to Rotterdam
and there’s an irradiation facility there an e beam where they radiate the
spices so they get rid of all the pathogens in there no no company who put
spices into their formula and say you’re making a frozen dinner you don’t spices
that contain salmonella in there and so that’s what they do and I FDA is just
come out with a risk assessment of spice of the spice industry and it’s pretty
bad okay so that’s where radiation is a very important tool I’m I’m curious when
you talk about that risk like of spices that have or have not been irradiated
for example how does that fall into like what’s the relative risk of that
compared to other things that we worry about in in most cases we put the spices
in like my spaghetti sauce and we cooked the hell out of it you know so that’s
going to inactivate it so we have very few incidents at the most it’s usually
something like pepper which is sprinkled on an egg or whatever and it’s not been
through the irradiation process in there so I mean I I think the risk is low
compared to eating a raw oyster or to eating sprouts and what’s the specific
risk on sprouts and then I’ll get up over to this question over here cuz I
heard some people kind of yeah gasp when we say well it’s the numbers are hard to
come about the in many cases it’s not a huge out it’s not an outbreak it’s
individuals and they don’t report it and so we don’t know I mean numbers that
I’ve seen from the CDC center for disease control and protection they
didn’t change it should be CDC p but they added on protection and name they
said that the risk was about 1 in 254 for e coli
for sprouts or for oysters I mean Jimmy John’s has had five outbreaks in
the last four years you know they still it’s interesting they will serve it at
their store and if you ask for sprouts and I was there today and I didn’t ask
for sprouts but I asked I ask the kid that was working as well he hates
letters but he loves sprouts you know and they if you go online to order and you
ask for sprouts a little window pops up and says there is a high risk of getting
ecoli or something like that I can’t remember words that and so they have it
on their website but not not in the store interesting I’m gonna head back
here and then I’ll come right back here can this isn’t food exactly but i’m
interested in the chemicals used to line packaging to line cans and align like
bags for chips and then are you gonna talk to us about the ice cubes that
melted oh yeah what was the times let me do that 722 crispness me this is a
little bit longer I was if I had big ice cubes apparently
it’s about nine minutes for the magic tray it’s about 15 minutes for the
building trade and it’s about two hours on the paper Ted can you grab the mic
and explain why that why that is and repeat those repeat those average
times
if with a with a large I forgot to take my ice cubes from home okay so I
went to the ice machine and they were wet and i cooled them down with it but
it didn’t work the on the paper it usually takes two hours for a typical
ice cube battery or freezer okay up for the aluminum tray maybe about 19 20
minutes in about eight minutes on the thing now why these differences okay has
to do with heat transfer there’s change there’s differences in heat transfer
between the three plates the plates act as fins okay you go to your radiator in
the car and you have pipes that are the radiator pipes but you see metal fins
all around okay that increases the heat transfer rate out okay so that’s that’s
one thing I try to keep them all about the same size but the plate thing is a
little bit long but the differences in the thermal capacity we call it thermal
diffusivity in the materials and so the paper plate has a very low thermal
diffusivity so it can’t transfer the heat and so won’t even act as a fin at
all and the aluminum a little bit better and the black plate you can do this
experiment home if you don’t have a magic tray all you have to do is use
eh-eh-eh-eh iron frying pan and it works just as well for doing that so it’s just
some engineering we use this in our engineering course to teacher but water
has some interesting properties and this all right so now what was it and the
second question was about the oat linings of cans and potato chip bags and
stuff like that the I mean that is a big concern the Food and Drug
Administration and the way that is regulated a a food package is a food
additive under the law a very interesting thing not only that but I
should mention that food irradiation is not a process it’s a food additive which
which is crazy and so you have to prove that the kinds of things and it’s not on
the surface it’s actually inside the plastic itself that the diffusion of the
material from the surface into the food over the shelf life of the food allows
for no more than about a half a part per billion in the solution and so they may
basis on the toxicology they make some decisions on that it’s not an easy area
it’s a real controversial area the BPA issue has been a big one for many years
on there and you’ve got big groups on both sides of it that are doing
toxicology and so we don’t know we really don’t know and I just I I’m gonna
get to your question next but i just wanted to it’s kind of funny to talk
about another cafe that’s coming up at this moment but I always kind of think
of our cafes is an ongoing conversation that they all kind of tie together our
may cafe will be about contaminants of emerging concern I can’t say for sure
that she’s going to be talking about BPA and such but she might be a person to
ask that question of when when the time comes the to let me just mention to the
two of the most interesting ones is and so now the meat industry is beginning to
do that is we have allowed for 4050 years for meat producers and poultry
producers to put low levels of antibiotics in the feed because that
improves the feed efficiency and the weight gain and stuff like that and what
we’ve now know is that all these antibiotics has led to severe increase
of antibiotic resistant pathogens and that we’re losing antibiotics to treat
diseases okay that’s my next thing that my
students are going to do with my class they’re going to write a scenario on
that it’s a really important one the other one is in water and Flint Michigan
is a good example but we have a real problem on the Mississippi River a
friend of mine who is a biology professor at st. Cloud State he studies
a very interesting small fish and looks at how it changes depending on where
it’s growing so he takes fish samples from above st. cloud before Minneapolis
after st. Paul and then at the bottom the end of Lake Pepin and this fish
increases a number of males fishes that become perm appetites and it’s almost
like 75 percent down in Lake Pepin and he attributes that that to the fact that
we use a lot of estrogen drugs especially for female hormone treatment
and about eighty percent of the drug goes out in your pee goes out into the
water treatment plants and water treatment plants don’t take that out of
the water and that’s why it increases going down I’d hate to drink water down
in New Orleans you know you know in fact we had a real problem with brown rice
that was being harvested it was about two years ago in a Mississippi and it
had like 40 times the level of arsenic in it and it was because the arsenic
comes down the stream and got into the water and got ingested by the plant in
there so I need a lot of concerns out there interesting oh let me it has to
make right over here I need to go back to the sprouts issue but if I grow my
own sprouts am I going to have the same problem with pathogens I mean is it the
way that the sprouts are handled for the restaurant industry or is it not
something about the sprouts themselves do you sit outside your garden with us
shotgun and chase away squirrels and birds I mean the the main organism our
Salmonella and e-coli okay if you grow a have a sprout form near a dairy farm
there’s a high chance of e.coli transmission in underground water in
especially Salinas Valley the dairy farms are on the hill and the vegetable
farms are in the valley and shit runs downhill yeah so so I mean you don’t
know well but I’m throwing them on my windowsill Oh even growing them inside
in your windowsill yeah so it’s not Oh probably probably not yeah you’re
probably okay the big problem is the I mean the biggest sprout outbreak was two
years ago in Germany okay Germany Ireland France and it was traced to
fenugreek seeds was harvested from seeds in Greece the seeds were shipped to in
Egypt the seeds were shipped to Greece where they were grown and the growing
conditions to grow the sprouts commercially is used 35c 37 degrees c
room so you get rapid growth and bigger growth and that’s the temperature where
organisms can grow the the organisms are embedded inside the seed itself but now
they can get out and start trading and this got into all different kinds of
restaurants all around Europe they thought at first the FSA the European
Food Safety Authority thought it was tomatoes from Spain and so they banned
all tomatoes from Spain that killed that industry they lost two hundred million
dollars that season and eventually they found that it was fenugreek okay so it’s
uh keeps on popping up we have all kinds of jimmy johns has had a lot of problems
with that and high quality restaurants as well
it’s not the restaurant it’s uh it’s the way it’s handled in there I’m
temperature room temperature the organisms will grow so that’s not you
know you’re not growing them in a refrigerator I’m sorry I’m feeling a
little guilty about the sprouts that i just bought at the co-op but i’m gonna
cross my fingers on this batch you know soak them in good scotch oh well I
didn’t realize that spouts were an issue i’m more concerned with mushrooms is
there an inherent danger there that I’ve always thought about they can kill you
yeah there’s there certain mushrooms that are very poisonous and we had now
he’s passed away we had one of the most prolific researchers here in Minnesota
Clyde Christensen and in his book about mushrooms he wrote a nice book of
mushrooms he had a quote in the beginning he says there are old mushroom
pickers and there are bold mushroom pickers but there are no old bold so the
the there’s actually a a different concern that the Swiss research labs
have shown in the typical white button mushroom that we have there is a
compound that’s produced called a garroting okay which is a carcinogen now
you’ve got a natural product producing a carcinogen and they recommend no more
than one mushroom meal per month I eat a lot of mushrooms you know you know I
mean another I mean another interesting one is concerned about fried foods and
not from the fact standpoint but the fact that in things like potatoes you
have some glucose that’s in there we want that for the Browning reaction
in in the fry and in the chip you want that color perform and we have the
potato has a amino acid pool that’s very high in disparaging a typical amino acid
that we it’s not a required amino acids but it’s in the structure of most
proteins and at high temperatures above about 130 degrees C the glucose reacts
with the asparagine to produce acrylamide which is a carcinogen okay
and the typical youth who eats a bag of potato chips and maybe a large serving
of french fries from McDonald’s they get in a day they get 80 times the loud
level for asparagine for a krill amide I mean and that’s you know we’re making it
in our home you know as well as an industry what do we do the I mean there
are some treatments that have come up of putting a enzyme in the solution that
you soak the potatoes in that will degrade the asparagine so you don’t get
that reaction yeah or or you fry it at lower temperature obviously it’s alright
how a good scotch every day you tell me I can tell you what’s my favorite food hi um you were talking a little bit
about how water action and water activity wasn’t really an idea that
people in your industry and area were accepting of and how there was this all
this argument going about it is that something is that a conversation an
argument that’s still occurring or okay yeah it’s not yeah I mean I’ve finally
convinced slate in laveen that water activity is important and in fact I’ve
published a couple of papers with them ok so we’ve solved that problem it was
you know they were they were not food scientists and they didn’t understand
what how we were using water activity and all that list of things the
paradigms that we came out of that we really critical for food safety is it
can you recommend a one or two sources of information to learn about just foods
in general and healthy foods and what to avoid and it also just a couple decades
ago there are questions about peanut butter and should peanut butter be
stored in a fridge or restored at room temperature because of some reaction
within the peanut butter now when the the I mean that was a story but the
water activity of peanut butter is low enough that you know yeah if you’re
going to store it for two years there’s a problem but critically which we don’t
have an answer for is a good way to inactivate the microorganisms that are
pathogens in the processing most nut plants in the United States were built
100 years ago and they’re not designed properly and in the peanut case of
america which 350 companies had we’re buying that peanut paste to make
crackers like Kellogg Kellogg’s had an Atkins brand they relied on us what we
call a certificate analysis from the company and so they didn’t go out and
inspect the plant Nestle did and the Nestle guy who went out inspected the
plant two years before the outbreak occurred said this was the worst plant
he ever so I mean it was holes in the roof there were residents all around the
plant itself dirty equipment and stuff like that his company decided not to
report that to the Food and Drug Administration and this is one of the
big debates that I’ve had in my class of should they have done that and it was on
on the exam yeah I mean it’s a it’s a real critical issue and you know the
there are there are ways that you can inactivate it but they use a propylene
oxide gas and you got to have a very special plant to do that pin
and there and uh it’s dangerous for workers to use and stuff like that so it
is a risk in there and again it came from birds and animals running in the
fields where the peanuts are the peanuts are on the ground and gets on the show
the peanuts get roasted but they shall it first hey and the shell produces a
lot of dust in the plant and after its roasted it’s sitting in a room where
this dust is coming down from the from the showing room and that’s the problem
you got to have a plant that’s built that allows for controlled air flows
away from the finished product in there and that was not done and in the worst
case in here which to me was the most egregious thing was the president of
company he not on a regular basis but he did send out a product from the plan
that had tested positive for salmonella and he wrote emails to his people we we
need the money send it out so he completely ignored the fact that he had
a positive Salmonella in there so with products that blend you’re talking about
water activity with products that blend dry and wet ingredients you you had
mentioned Raisin Bran for example you’ve got raisins in with crispy pieces any
number of examples of that what do they do in the process to keep that water
from transferring or do they just say well you better eat this quick well you
could put a shorter shelf life on the package that’s one thing but Kellogg’s I
did some work with them if you take and soak the raisins in glycerol you know
which is part of a fatty fatty acid molecule triglyceride map molecule you
can lower the water activity down low enough and the glycerol is liquid at
room temperature so it acts as a plasticizer so it replaces the water and
you can get soft raisins so they’re raised its rice and rye now have the
glycerol soaked raisins in there that’s one way again you got a
name of a compound and most people say oh I can pronounce it but what the hell
is this thing you know I don’t want to eat that well you’re eating every time
you eat fat you know so is it but that’s one way to do it and there I mean people
are working on edible barriers but we have found that the only good edible
barrier is chocolate or Scotch it sounds like my god that’s a barrier to eating I
hate to close off with a simple question but is microwave cooking going to kill
Salmonella yes yes yeah yeah so cook cooking giving the right heat treatment
so okay on meat products I mean here’s a point out some of the stupidities in our
regulatory system under Food and Drug Cosmetic Act okay a food is adulterated
if it contains any poisonous or deleterious substance and under court
cases that have been held FDA the present detection methods we have today
we can detect one organism / 25 grams on a weight basis that’s one in one part in
10 to the 14th parts that’s a very small number I’m working on some rapid
techniques and new techniques to better detect that and so any pathogen if you
detect it you can’t ship the food and if you ship it and somebody gets ill bill
marler how to Seattle is going to sue you for it in meat meat is not food meat
is under the wholesome meat act different act okay so meat poultry with
a was it the no fish is food okay I mean this is crazy buffalo buffalo is food
it’s not neat yeah this is crazy but back in 1974 the American public health
sociation sued the USDA Earl but was then the secretary that they the a PHS
wanted them to declare Salmonella as a pathogen we know what the pathogen USDA
says no it’s not a pathogen and and the judge ruled sort of their favors they
said okay what you should do is come up with some way of educating the consumer
to cook ok so that was 74 took the US Department of Agriculture 20 years 20
years to come up with that little white label that you see on raw meat and it
says cook thoroughly he’ll keep refrigerated what the hell is cook
thoroughly mean yeah you know I mean that’s it’s a real problem i have a
patent of an invention that i worked with on 3m of a little tag that fits on
the top of let’s say you buy a meal that has meat in it and stuff and it’s a
strip of white with two blue ends and when it reaches 60 degrees centigrade
the the blue it’s basically wax melts and it moves to the center and when it
reaches the center so there’s no more white that means the product is done so
done this indicator but the doneness is based on how long you need to eat to
kill Salmonella in there and um I mean I just I think that and right now the
rules that USDA has leads to the fact that one in every pieces of poultry that
you buy at a for one out of four twenty-five percent probably has
salmonella scary so cook thoroughly meaning up to about 165 Fahrenheit for a
couple of seconds that’s that’s enough because there’s he there’s kill going on
all the way and that would give you the thing and the big problem more than
anything else is not just the cooking but the what we
call the cross contamination in handling of the product because it’ll get on your
hands you know let’s say you’re preparing chicken and you’ve cut it up
in pieces you put it in a in a baking pan and you take it over to the oven
open the oven door put it in okay and then oh yeah I gotta wash my hands so
now I go wash my hands okay now I prepare something else and then I oh I
better check the chicken so I go over open the door okay now you got organisms
on your hand you go back and you mix the lettuce with your hands and you’ve got
cross-contamination we don’t think about it that way you know I scare most of the
students in my class I teach a class called food safety risk and technology
and the women in the class say this is the best class and learning how to avoid
eating calories so I have to last quick questions for you the first is it just
say yes or no would you eat a rare burger you know okay no man to be a
tough cafe to go home afterward but by the way if you want a really good burger
halftime wreck on Front Street in a st. Paul it’s a right near Gabe’s on senega
it won the best hamburger in the Twin Cities ah about two months ago 0 2 weeks
ago yeah okay I’m burger well and then my second question for you is just to
wrap it up I know a lot of people in here our home gardeners really
interested in you know getting organic less processed foods etc etc um would
you know for the home gardener or somebody who’s processing food at home
more so than from a you know rahhhr state I guess what are your
recommendations and also would you do you err on the side of more processing
or less processing when you think about nutrition and health and food well we
can’t we can’t supply the world with fresh food that’s from so we you know we
in the Romans learned that and that’s where processing first started so some
process is good we we got to have good processes
that that are safe you know whatever and uh yeah local is better but organic a
good example I can’t remember which state just about a month ago one of the
state’s I think it was Virginia passed a law that you can sell raw milk okay and
one of the Senators brought bought some brought it to the west virginia okay
brought it to the state capital everybody drank it and they all got sick
and then the the largest organic milk farm in california they they make raw
milk and here’s what i think is a the wrong thing is that people bought it
they brought it home and they had their kids drink it I mean they can make a
choice I don’t think they should be feeding their children at and eight kids
are in a hospital with two of them with H.U.S syndrome you know I’m oolitic you
were enix and they’re going to be on dialysis for 20 years yeah that’s a
shame all right well thank you so much for being here tonight

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