Safety Concerns Related to Reduced Oxygen Packaging
Here an overview of food microbiology is provided. It starts by describing the different groups of microorganisms associated with food, such as molds, yeasts, and bacteria. It then focuses on bacterial reproduction, spore formation and the factors that affect bacterial growth and survival. The last part of this lecture focuses on bacterial pathogens associated with food, the disease they cause and processing factors that may be used to control them in reduced oxygen packaged foods.
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[00:00:04.920]So we have seen this graphic up here today already
[00:00:10.520]in one of our previous lectures and for this lecture,
[00:00:14.640]we're gonna focus our attention on the last block here.
[00:00:18.400]For safety concerns, we're gonna talk
[00:00:21.192]a little bit about the microbiology
[00:00:22.410]and the microorganisms that might be associated
[00:00:24.420]with these products and what can we do to prevent them
[00:00:28.220]from becoming an issue, from becoming a hazard,
[00:00:31.020]for a consumer in the food
[00:00:35.060]and we're also gonna talk a little bit about sanitation.
[00:00:37.700]That's our last lecture.
[00:00:41.760]So microorganisms are present in foods naturally.
[00:00:46.570]That's just the nature of the world that we live in.
[00:00:50.600]Nothing that we eat is necessarily sterile
[00:00:54.890]unless you are purposefully being fed a diet
[00:00:59.160]that's prepared for you for whatever reason.
[00:01:02.260]If you're sick in the hospital then yeah,
[00:01:04.040]maybe you might be fed something that was more processed
[00:01:09.090]to be sterile but in general,
[00:01:11.672]the foods in the environment that we live
[00:01:14.413]has a lot of microorganisms and it's just normal
[00:01:18.136]to encounter them in our daily lives.
[00:01:21.176]But raw foods will contain microorganisms and basically,
[00:01:31.176]part of our job is try to prevent them
[00:01:33.530]from growing out of control and spoiling the products
[00:01:36.950]or becoming a food safety hazard for the consumers
[00:01:40.820]so they're there and some of them are good,
[00:01:44.040]some of them we want to be there
[00:01:46.540]because they might transform our product
[00:01:48.410]in microorganism ways and things that are of our interest
[00:01:53.317]and sometimes they are there
[00:01:54.616]and they might spoil the product
[00:01:55.880]or they might cause sickness
[00:01:56.980]and those are the situations that
[00:01:58.260]we want to prevent from happening.
[00:02:00.640]The microorganisms that we will be discussing today
[00:02:03.450]include molds, yeast, bacteria, and viruses
[00:02:06.707]and we're gonna give a little bit of introduction
[00:02:08.800]to each of them so you can better understand
[00:02:11.690]how they may be associated with the foods,
[00:02:13.780]how they grow, and then what can we do to control them
[00:02:17.100]specifically when we talk about reduced oxygen packages.
[00:02:20.870]So molds are multicellular organisms
[00:02:23.380]meaning that they have several cells
[00:02:26.280]that make up an organism just like us.
[00:02:30.140]They reproduce themselves by
[00:02:31.720]fruiting bodies that we care spores.
[00:02:34.760]I like to compare them to plants
[00:02:38.220]because they have these spores, they kinda work like seeds
[00:02:41.653]so they produce them and then they can be spread with air
[00:02:47.280]within and they can go places and they can land
[00:02:51.290]in the surface of food products or equipment
[00:02:54.340]and if there's any moisture, any nutrients there,
[00:02:57.380]they can grow and start a new organism and from there,
[00:03:02.790]they produce, they grow and multiply themselves
[00:03:05.870]to the point that we can actually see.
[00:03:08.030]Eventually, you may see a piece of bread be moldy
[00:03:11.190]or fruits and vegetables get moldy
[00:03:14.637]and they're larger than bacteria and yeasts
[00:03:17.600]if we look at them under the microscope,
[00:03:20.519]you'd be able to visualize them with less magnification
[00:03:24.250]but in general, we can only see them if they grow enough
[00:03:27.990]in a product to make a colony
[00:03:30.420]and by the time you can actually see,
[00:03:32.560]there's millions of them there.
[00:03:35.460]They're widely distributed in the soil, in the air,
[00:03:38.670]and they'll survive in many substances.
[00:03:40.470]They don't need much to grow.
[00:03:42.940]Just a little bit of moisture and some source of light.
[00:03:46.850]So you can even see them growing in cardboard boxes,
[00:03:51.090]drywall, they don't need a lot of nutrients.
[00:03:54.610]Give them the right conditions, they'll grow anywhere.
[00:03:57.090]And they're more tolerant to cold than heat.
[00:03:59.710]What this means is that for the food environment,
[00:04:04.560]we can kill them fairly easy if we heat up our foods
[00:04:08.840]but it will spoil things that we put in the refrigerator
[00:04:12.110]which kind of makes sense, right?
[00:04:13.700]Cheeses, products that you usually put in the refrigerator,
[00:04:17.580]they might eventually get moldy.
[00:04:24.547]Yeasts are unicellular so now we're talking about
[00:04:28.030]an organism, the whole organism is one cell.
[00:04:31.735]They're smaller than molds but larger than a bacteria
[00:04:36.040]when we're looking at them under the microscope
[00:04:38.648]and then they'll reproduce themselves by budding,
[00:04:41.528]that's what we call it.
[00:04:42.525]And basically what it is, it's a mother cell.
[00:04:44.200]It's gonna produce a daughter cell that's attached to it.
[00:04:50.008]So you can see here in this picture
[00:04:51.490]that you have the mother cell
[00:04:53.100]and then it starts producing a daughter cell on the side
[00:04:56.435]and once this little daughter cell
[00:04:59.629]kinda has everything that it needs to survive on its own,
[00:05:01.830]it gets detached from the mother cell
[00:05:04.669]and becomes a new organism.
[00:05:05.502]So one organism becomes two, two might become four,
[00:05:09.789]and that's how they reproduce themselves
[00:05:11.490]and we microbiologists actually call that growth
[00:05:15.260]so when we say oh, the bacteria is growing,
[00:05:17.480]it doesn't mean that it's actually growing in size.
[00:05:19.500]It's multiplying itself and we talk a lot about
[00:05:23.470]how we might prevent bacteria growth,
[00:05:26.190]that's preventing them from multiplying themselves.
[00:05:29.620]It's widely found in nature,
[00:05:31.440]associated with liquid foods that have high sugar and acid.
[00:05:35.032]So if you have juices, sometimes that's the bacteria
[00:05:38.312]that might be spoil, or I'm sorry,
[00:05:41.580]the microorganism that might be spoiling that juice
[00:05:44.991]in the refrigerator or jams and jellies in the refrigerator
[00:05:47.955]that might be spoiled by this type of microorganism.
[00:05:52.435]Then we come to bacteria which is the most
[00:05:54.709]important and troublesome of them because
[00:05:57.155]they are the ones that can actually cause sickness.
[00:06:00.200]They can cause foodborne illnesses.
[00:06:02.860]They can produce enzymes that will spoil the product.
[00:06:07.080]Because these microorganisms,
[00:06:11.366]the way that they feed themselves
[00:06:12.587]is by sending out all of their enzymes
[00:06:14.700]out in the environment so the enzymes
[00:06:16.510]can do the digestive job for them
[00:06:19.110]and then they can absorb simple nutrients.
[00:06:22.707]They're not like us.
[00:06:23.540]We ingest the food and then our stomach
[00:06:26.730]will do that digestion for us.
[00:06:28.600]They have to actually do that in the food
[00:06:31.160]so they send out the enzymes
[00:06:33.630]and that's when our products are changing color,
[00:06:36.180]changing flavor, because things are literally
[00:06:38.980]being digested or changed by those enzymes
[00:06:44.771]and that's just part of how they are feeding themselves.
[00:06:48.260]In that process they may also send out toxins.
[00:06:52.670]It's just part of how they grow, multiply themselves,
[00:06:55.820]and things that they're producing as part of that process
[00:06:59.300]and those toxins can cause illnesses
[00:07:02.317]so that's when we encounter with intoxication,
[00:07:07.870]Single cells and microscopic.
[00:07:10.650]Those are characteristics of this group of microorganisms
[00:07:13.397]and they may come in several shapes and forms.
[00:07:17.140]They might be like little rods
[00:07:19.639]or they might be round and depending upon
[00:07:23.261]how they're shaped, it might be part of their name
[00:07:26.381]so there's some bacteria that we call basalis
[00:07:30.182]because it's a rod shape.
[00:07:31.030]Some bacteria we call it micrococcus
[00:07:36.170]because they're little round shape.
[00:07:37.456]So they come in many shapes and forms
[00:07:38.930]and the last group that I wanted to discus with you
[00:07:41.480]is the virus.
[00:07:43.480]These are small infectious agents that replicate
[00:07:47.340]only inside of living cells.
[00:07:49.560]So they don't have necessarily the ability to grow in foods.
[00:07:53.660]You're not gonna replicate in the food.
[00:07:55.480]They might replicate in people and people may
[00:07:58.259]contaminate the food and then the food becomes
[00:08:00.334]a source of contamination to somebody else.
[00:08:04.100]Somebody else will ingest that food and then will get sick.
[00:08:08.419]We're gonna see it a little bit here
[00:08:10.740]in the next couple slides.
[00:08:12.600]It's the reason for the maturity of the foodborne illnesses
[00:08:16.819]is transmitted by viruses.
[00:08:20.557]While not inside of a cell,
[00:08:21.760]it exists as a viral particle made of different parts.
[00:08:25.274]Our slide here shows that there's a genetic material,
[00:08:29.030]a protein coat, and an envelope.
[00:08:31.200]In some cases, that might be part of that viral particle
[00:08:35.260]and it's very, very small.
[00:08:38.200]This type of microorganisms,
[00:08:42.237]they're very, very small because they can actually even
[00:08:44.873]move back a bacterium so they're much smaller than bacteria
[00:08:53.094]and however they're very, very troublesome
[00:08:55.875]and we'll see that in a couple slides.
[00:09:00.179]Now we're gonna focus a little bit on the bacteria
[00:09:04.600]and we're gonna discuss how they grow, multiply themselves,
[00:09:08.360]and what are the factors that we can use to control
[00:09:12.861]that process because they're the ones
[00:09:14.600]that can cause disease the most
[00:09:17.978]and they are the ones that we can actually control growth.
[00:09:19.950]Virus and virus infection and foodborne illness
[00:09:23.027]caused by virus are mostly prevented through sanitation
[00:09:28.860]because they don't grow in the food.
[00:09:31.357]The food is just a mechanism for them to spread themselves
[00:09:35.180]to other people.
[00:09:36.170]They go from one people to another
[00:09:38.057]and we're gonna talk about sanitation in our next lecture.
[00:09:41.460]So for this lecture, we're gonna focus on the bacteria
[00:09:45.437]and how we can control.
[00:09:47.259]So like I was saying, one microorganism or one bacteria
[00:09:50.090]can multiply themselves into two
[00:09:53.261]and the way that they do that is by
[00:09:55.020]fission or division and we can see that in this slide.
[00:09:57.299]So you have one organism that basically start
[00:09:59.501]enlarging itself a little bit and doubling
[00:10:05.130]everything that he has inside of that cell
[00:10:08.593]to the point that it can become two separate cells.
[00:10:10.380]When that happens, then a wall gets formed
[00:10:13.660]between the cells and then each splits into two organisms
[00:10:16.396]so from one, it goes to two, two goes to four,
[00:10:20.499]and even though we might start kind of slow,
[00:10:25.240]when you get to the thousands,
[00:10:28.477]that multiplication factor goes up really fast.
[00:10:31.630]So they can multiply themselves quite fast
[00:10:36.270]because of this division that they are able to go through.
[00:10:42.210]So under optimum conditions, this whole process
[00:10:45.750]may take 20 to 30 minutes meaning that
[00:10:50.010]if you have a food that is being exposed to a temperature,
[00:10:59.923]foods that should be refrigerated but are not,
[00:11:01.700]so now you are putting that food perhaps under
[00:11:04.040]optimum conditions for this bacteria to grow,
[00:11:07.040]they're gonna be multiplying themselves
[00:11:08.660]every 20 to 30 minutes and you can put yourself
[00:11:13.060]in a situation of high risk fairly quick.
[00:11:16.990]This chart shows us that nonetheless,
[00:11:20.680]different bacteria will have different times
[00:11:25.220]that are required for them to divide themselves.
[00:11:29.300]So some of them will have a generation time
[00:11:32.947]and that's what we call.
[00:11:34.925]Generation time is the amount of time for one bacteria
[00:11:36.560]to split into two.
[00:11:37.700]So that may take 20 minutes as you can see
[00:11:40.290]so they can, in a matter of minutes or hours here,
[00:11:46.160]they can multiply themselves fairly quickly
[00:11:48.910]from maybe one individual all the way to 650 cells
[00:11:53.827]if they do that every 20 minutes
[00:11:56.250]and if they take 30 minutes or 40 minutes,
[00:11:58.580]then they're not gonna grow as fast but they're still
[00:12:00.910]gonna go through that process of multiplication.
[00:12:06.700]There is among the bacteria one special group that's
[00:12:13.331]of concern, much concern, for the food industry
[00:12:16.079]in the food service because they can produce spores
[00:12:21.080]and the reason they do it is because
[00:12:25.891]the bacteria has this instinct for survival.
[00:12:29.629]So when they are in an environment that they encounter
[00:12:33.230]situations that they might sense that it's not going well
[00:12:36.570]for them because they don't have enough nutrients,
[00:12:40.453]the temperature may be too high or too cold,
[00:12:42.030]whatever it is that's stressing them
[00:12:45.032]and they're feeling that maybe they won't survive this,
[00:12:47.630]they kind of pack all they're information,
[00:12:50.750]they pack all they're DNA information
[00:12:52.630]and everything that they need to multiply
[00:12:55.170]and continue their species into this little capsule
[00:12:59.520]inside of their bodies or their cells.
[00:13:02.560]So here is a diagram that kind of shows that process.
[00:13:07.592]So you have a vegetative cell.
[00:13:08.830]This is how we call it a cell that's just growing
[00:13:12.820]We call them vegetative.
[00:13:14.420]So you have a vegetative cell
[00:13:16.020]that might have sensed that the environment
[00:13:18.170]is not going their way in terms of nutrients
[00:13:22.160]or temperature so the instincts for survivability
[00:13:26.595]and they start forming that spore inside of the cell
[00:13:31.955]and then when that spore gets ready to be released,
[00:13:35.590]it will be released in the environment
[00:13:37.617]and that may happen when that cell dies
[00:13:40.060]so if the temperature or the nutrients
[00:13:42.340]really get to the point that the bacteria would not survive,
[00:13:47.539]the cell will die but that spore will survive
[00:13:51.240]and bacteria has evolved in nature to point that
[00:13:57.940]this spore here, it's a lot more resistant
[00:14:01.610]to any environmental condition than the cell
[00:14:05.517]that it was created by.
[00:14:06.420]So it will survive much higher temperatures,
[00:14:09.650]it will survive much dryer conditions,
[00:14:11.830]it will survive sanitizers that we might use,
[00:14:16.770]We may be able to kill the vegetative cell
[00:14:18.980]but we would not kill the spore.
[00:14:21.160]And then when this spore is in an environment
[00:14:25.150]that encounters conditions that
[00:14:27.450]is good again for it to grow,
[00:14:29.630]it will germinate into a vegetative cell again
[00:14:32.537]and it will start that cycle of
[00:14:36.559]growing and multiplying cells
[00:14:37.571]so it's kind of like a survivability tool
[00:14:38.540]that the bacteria has and why is it important?
[00:14:42.934]It's because the conditions of cooking, chilling, freezing,
[00:14:46.710]everything that we do in
[00:14:49.720]the food industry except for canning
[00:14:52.701]cannot kill this spore.
[00:14:54.150]So if this bacteria is able to produce that spore,
[00:14:58.580]it will survive our heating, it will survive our cooking,
[00:15:03.010]and we need to use perhaps other tools,
[00:15:05.920]other hurdles, other means to prevent them
[00:15:10.090]from ever becoming a vegetative cell again
[00:15:12.960]because if it hangs in the food in the form of spores,
[00:15:16.562]it's not gonna make anybody sick
[00:15:19.480]but if it becomes a vegetative cell
[00:15:21.110]and starts growing again,
[00:15:22.390]it might produce toxins and that's when problems arise.
[00:15:26.600]So our job in the food industry,
[00:15:30.180]for the most part of the products that we make
[00:15:32.570]and most of the processes that we use,
[00:15:34.550]food service and food industry,
[00:15:37.170]we kill the vegetative cell and we do
[00:15:41.103]everything in our power to prevent that spore
[00:15:44.159]from ever becoming a vegetative cell again.
[00:15:45.490]The only process that we do by nature
[00:15:48.490]that actually will kill the spores is canning,
[00:15:54.500]You can do that home canning as well
[00:15:56.640]as long as you do it well, using high enough temperatures.
[00:16:00.750]But it's not the types of processes that we're necessarily
[00:16:03.840]discussing here today.
[00:16:07.220]So then it becomes the question how can I prevent bacteria
[00:16:11.140]from multiplying itself fast or maybe
[00:16:14.450]how can I prevent this spore from germinating
[00:16:16.970]because that's how we're gonna,
[00:16:19.780]those are the tools that we're gonna be using
[00:16:22.741]to ensure that the food that we make is safe.
[00:16:25.730]So this is basically our little toolbox
[00:16:28.440]is what I call it.
[00:16:30.602]It's the toolbox.
[00:16:31.435]Those are all the factors that might affect,
[00:16:34.720]in one way or another, growth and survival of bacteria
[00:16:37.757]and other microorganisms in food
[00:16:40.485]and depending upon the situation
[00:16:42.980]and the process that we're doing,
[00:16:45.423]we might be using one tool versus another
[00:16:47.480]so when we're cooking or using temperature to kill it,
[00:16:51.150]when we're doing acidified products like tomato sauces
[00:16:55.130]and salsas or using the pH
[00:16:57.680]in combination with mild temperatures.
[00:16:59.630]So we can use different tools to control the growth
[00:17:02.821]and the survivability of the organisms.
[00:17:05.750]We're gonna go through each of them very briefly
[00:17:08.885]just to kind of explain to you how they work.
[00:17:12.340]So nutritional requirements.
[00:17:14.430]Different bacteria will have different
[00:17:18.543]nutritional requirements and sometimes,
[00:17:19.822]you can use that to prevent them from growing in places.
[00:17:22.690]However, when we talk about foods in general,
[00:17:26.270]that's not a very good tool because
[00:17:27.930]we do want our foods to be nutritional,
[00:17:30.885]oblique with nutrients, we want it to be appealing.
[00:17:33.082]So we're losing some of this,
[00:17:38.840]nutrients may not be an option but I just wanted you
[00:17:43.182]to know that different microorganisms
[00:17:45.355]will have different nutrient requirements.
[00:17:47.170]Some of them will require an environment
[00:17:49.740]with more vitamins and minerals to be able to grow
[00:17:53.962]and some other bacteria will grow in foods
[00:17:55.920]that are less rich in those nutrients.
[00:18:01.550]Moisture, this is a very good tool for us
[00:18:04.660]because as I mentioned a little bit earlier today,
[00:18:07.810]bacteria will only be able to feed themselves
[00:18:11.030]if they can reach out to the environment
[00:18:13.839]and have those nutrients come to them
[00:18:17.100]and water is how things move around in our food products
[00:18:20.145]and that's how the bacteria can actually reach
[00:18:26.063]So if we don't have any water available to move around
[00:18:27.930]and carry things, the bacteria cannot
[00:18:31.151]get a hold of those nutrients so if you take moisture out,
[00:18:36.490]we can definitely reduce microbial grow.
[00:18:41.630]Cases or examples of food processes that we do that,
[00:18:46.573]can you think of anything?
[00:18:54.778]Anything at all with any foods
[00:18:57.256]that we preserve by removing water?
[00:18:59.980]Maybe like sun dried tomatoes.
[00:19:06.639]Dried fruits, dried vegetables, and I'm sorry.
[00:19:10.517]You remove water, yes, yep, during that process
[00:19:14.290]and some others like we might not even think about.
[00:19:17.410]Every time you bake something,
[00:19:19.460]the final product has much less water
[00:19:21.393]than the initial dough or batter.
[00:19:24.660]So we remove water quite a bit when we process
[00:19:27.884]or cook foods and that's how we help
[00:19:32.387]or why our final products may last much longer
[00:19:37.890]than your raw ingredient.
[00:19:41.840]This is a concept that is very much related with moisture
[00:19:46.010]but it has a twist to it so moisture is basically
[00:19:51.790]the total amount of water that you have.
[00:19:54.425]The amount of water in your product
[00:19:57.914]you can define as the amount of moisture.
[00:19:59.530]But some of this water may be busy
[00:20:03.550]binding itself to components of your product,
[00:20:06.810]some molecules that are part of that product,
[00:20:12.170]and they're not necessarily available to move around.
[00:20:15.990]Remember when I said that the bacteria needs water
[00:20:19.130]moving around to be able to bring the nutrients to them?
[00:20:22.802]So now if I remove or if I reduce
[00:20:28.888]the amount of water that can move around,
[00:20:29.960]the water might be there but if that water
[00:20:33.060]is bound, stuck in place, we cannot help the bacteria.
[00:20:37.680]So I can have a moist product
[00:20:40.270]that doesn't help bacteria grow
[00:20:42.970]because that water now, it's not able to move
[00:20:46.190]or bring the nutrients to the bacteria anymore.
[00:20:49.280]So the water that is available for the bacteria to grow,
[00:20:52.820]that's what we call the water activity.
[00:20:55.440]So the more water available to move around in food,
[00:20:58.900]the higher is the water activity of the product
[00:21:02.740]and that's influenced by the water binding capacity
[00:21:05.360]of the ingredients.
[00:21:06.610]Some ingredients are really good at binding with water.
[00:21:09.820]Salt, sugar, would be the two main examples.
[00:21:13.750]Products that have a lot of sugar in it,
[00:21:16.670]they may have water and they may look moist
[00:21:19.580]but that water is no good for bacteria to grow
[00:21:22.210]because it's busy being bound and stuck by the sugar.
[00:21:27.000]Let me see what I have here in my next slide.
[00:21:32.288]There we go.
[00:21:33.820]And different microorganisms will have
[00:21:37.660]a different amount of water that they require
[00:21:42.680]for their growth and that's the water activity
[00:21:46.280]that we are talking about.
[00:21:47.810]Some of them, as you can see like molds,
[00:21:50.710]will require 0.75 water activity.
[00:21:55.173]Yeasts will require more so right now,
[00:21:57.490]I just want you to compare the numbers here.
[00:22:01.000]Clostridium, salmonella, and staphylococcus aureus
[00:22:04.140]will require quite a bit more water than yeast and mold.
[00:22:08.540]What does it tell us?
[00:22:10.474]It tells that first, bacteria,
[00:22:13.890]it's a lot more picky in terms of where they grow.
[00:22:20.693]They need a lot of free water,
[00:22:21.550]otherwise they can't grow and the pathogenic bacteria
[00:22:28.030]that needs the least amount needs 0.85.
[00:22:33.914]So that number, it's very important in terms of food safety
[00:22:39.960]because if not, you have a product that's below 0.85,
[00:22:45.460]pathogen bacteria cannot grow anymore
[00:22:48.560]so it becomes like a line that we draw
[00:22:55.486]for food safety in terms of water available.
[00:22:59.370]But you might be asking yourself where
[00:23:01.160]this number is coming from, 0.75, 0.85, what does it mean?
[00:23:06.520]So basically, the way that we measure water activity
[00:23:09.663]is you use machines like tabletop machines
[00:23:12.680]in the laboratory that actually
[00:23:14.980]make this measurement for us.
[00:23:17.670]It all depends on water, like pure water.
[00:23:22.559]So if I had a glass of water
[00:23:23.392]and I put a little bit of that water in my machine,
[00:23:26.810]my machine's gonna tell me that the water activity
[00:23:30.058]of that glass of water is one.
[00:23:32.440]Everything else, every other product,
[00:23:37.259]is gonna have less than one.
[00:23:39.023]The more ingredients, the more components
[00:23:43.181]I add to that glass of water,
[00:23:45.039]the less water is free to move around
[00:23:47.580]and my water activity starts being reduced.
[00:23:50.821]So if I have water and I have milk,
[00:23:54.300]water will be probably around one.
[00:23:58.483]Water is gonna be one.
[00:24:00.040]Milk is gonna be probably 0.99 or 0.98.
[00:24:04.920]If I have now maybe another product
[00:24:10.150]that it's a lot more, let me think, a milkshake.
[00:24:15.230]Going from milk to a milkshake where you added
[00:24:18.380]other ingredients, you might add some things
[00:24:20.673]to make it thicker, you might have fruits and more sugar,
[00:24:25.100]that will have a water activity that is even lower,
[00:24:29.300]maybe in the range of 0.9 but still
[00:24:33.386]is gonna be pretty high because that milkshake
[00:24:34.520]will spoil fairly easily, wouldn't it,
[00:24:37.101]if I don't put it in the refrigerator
[00:24:38.120]or if I don't do anything with it.
[00:24:40.750]So that's where the water activity is.
[00:24:45.900]One thing that I always think is interesting is how
[00:24:51.387]the water can be bound in the product and we don't realize
[00:24:54.140]so if we were to compare and I don't think,
[00:24:58.820]let me see here, yeah, I don't have a table
[00:25:04.050]in this presentation but we can just talk about it
[00:25:07.073]a little bit.
[00:25:10.033]If I were to compare the amount of water activity
[00:25:15.380]in different products, you would think that a piece of bread
[00:25:22.900]for example because the way it presents itself,
[00:25:27.480]it's a solid product, the amount of water activity
[00:25:32.990]that we have in bread, believe it or not,
[00:25:36.890]it's higher than the amount of water activity
[00:25:39.460]that we would have in the jam that might spread
[00:25:43.233]on top of the bread because that jam
[00:25:46.550]has a lot of sugar and the water might be there,
[00:25:52.810]might make your product very smooth and spreadable,
[00:25:56.806]but it's not available for bacteria to grow
[00:25:59.270]or for molds to grow so in a sense,
[00:26:02.030]your bread would spoil faster than your jam
[00:26:06.770]because the bread will have a higher water activity.
[00:26:10.620]For the most part, depending upon
[00:26:13.206]the recipe of the bread, of course.
[00:26:14.270]But for the most part, if we just looked at bread,
[00:26:16.006]a regular recipe of bread, compared to jam
[00:26:18.945]which is then interesting because
[00:26:20.920]you would perhaps expect to have more water activity
[00:26:24.000]in the jam, right, because it's a spreadable product.
[00:26:28.630]Okay so moving on, oxygen requirements.
[00:26:32.720]The different bacteria will have different requirements.
[00:26:35.160]Some of them will like oxygen.
[00:26:37.780]They will require oxygen for them to grow just like us.
[00:26:40.870]If you take oxygen out, what happens to us?
[00:26:46.098]We're pretty much dead.
[00:26:47.366]It won't take long.
[00:26:48.290]I don't know if I can hold my breath for more than like
[00:26:52.326]more than a minute and a half, I don't know.
[00:26:54.545]Wouldn't even try.
[00:26:56.566]But they work pretty quickly.
[00:26:57.510]In the case of the bacteria, we may not kill them
[00:27:01.480]because they're pretty resourceful.
[00:27:03.825]They're just gonna sit quiet there and not grow
[00:27:07.142]and then when you give oxygen back, they start growing.
[00:27:10.090]They're better than us in that regard
[00:27:11.860]'cause we would pretty much die but they will not die.
[00:27:14.406]They will just sit quietly there in the product.
[00:27:17.950]Some others don't like oxygen.
[00:27:22.030]They are only gonna grow if you remove the oxygen
[00:27:25.720]and in some cases, that's a big deal because
[00:27:30.723]what are we here for today?
[00:27:35.360]So there's bacteria that's gonna grow
[00:27:38.250]exactly when you do that and that's our concern.
[00:27:42.680]And different groups will behave differently
[00:27:45.470]and some of them are vegetative.
[00:27:47.730]That means that they don't care.
[00:27:49.600]They will grow either way,
[00:27:51.505]in the presence or absence of the oxygen.
[00:27:53.810]Temperature is another characteristic.
[00:27:55.830]Different bacteria will prefer different temperatures.
[00:27:57.834]Some of them are adapted to grow at a higher temperature,
[00:28:02.560]some at a more ambient temperature,
[00:28:05.850]and some at refrigerated temperatures.
[00:28:08.806]Why do we care?
[00:28:09.639]Where do we keep a lot of our products
[00:28:11.526]that we try to increase shelf life?
[00:28:14.050]What do we do with it?
[00:28:16.120]We refrigerate it.
[00:28:17.460]Even when we refrigerate, we are preserving the product
[00:28:21.380]and preventing all the ones, all the bacteria that
[00:28:26.440]fits or falls into this part of the chart here
[00:28:31.220]will be prevented from growing and that's great.
[00:28:34.370]That gives us a lot more shelf life for our product
[00:28:36.849]but there's this little group here that's still gonna grow
[00:28:41.490]so that's why even under refrigerated conditions,
[00:28:44.260]we have limits in time.
[00:28:46.840]That's why very soon here,
[00:28:49.770]we're gonna be talking about you keep it refrigerated
[00:28:52.250]but no longer in a certain amount of time
[00:28:55.390]because this group over here,
[00:28:58.885]they kind of grow slow because the temperature,
[00:29:00.966]it's not very favorable but slowly but surely,
[00:29:04.262]they'll get there so give it enough time,
[00:29:07.585]they'll become an issue, too.
[00:29:09.350]So there's pathogenic bacteria that falls into
[00:29:11.700]that category, listeria is one,
[00:29:14.523]that they like growing under lower temperature conditions.
[00:29:17.900]They're kind of slowly doing so
[00:29:21.185]so they give us a little bit of time
[00:29:22.742]so we can keep foods in the refrigerator
[00:29:24.486]for a certain period but we can't keep them there
[00:29:26.330]because even the refrigerator,
[00:29:28.310]we're not gonna forever prevent it from growing
[00:29:31.618]so that's the importance of keeping an eye on the time.
[00:29:34.980]How long are you gonna keep things refrigerated?
[00:29:38.740]And temperature, if we increase a temperature high enough
[00:29:42.850]like cooking temperatures, then we're actually killing it.
[00:29:44.980]Then finally, we're getting to the point of killing it,
[00:29:48.721]not just prevent it from growth or inactivating them
[00:29:52.887]but we're only gonna kill which ones,
[00:29:54.450]vegetative or spores?
[00:29:58.840]Spores are gonna still sit there
[00:30:00.614]and if you don't do something afterwards,
[00:30:02.480]they may come back so that's the point
[00:30:05.170]and the higher the temperature here,
[00:30:07.270]that's what I want to show in this chart.
[00:30:09.070]The higher the temperature, the faster we can kill
[00:30:12.920]the bacteria so this is the population of bacteria.
[00:30:16.430]By increasing the temperature here,
[00:30:18.440]we can then reduce a lot amount of time that is required
[00:30:23.230]for killing the bacteria.
[00:30:26.780]pH, that's the degree of acidity or alkalinity
[00:30:31.336]of the product.
[00:30:32.700]Most food products, we can kind of see here in this chart.
[00:30:36.380]Most food products are gonna be on the neutral
[00:30:40.330]or even like slightly acidic to acidic
[00:30:43.620]so we'll have milk here goes to neutral
[00:30:47.140]and everything else that's kind of down from there
[00:30:51.600]and yeast and molds will be able to grow at a lower pH
[00:30:57.240]so they tend to spoil in growing products
[00:31:00.760]that are in this area over here
[00:31:02.740]while bacteria might like better this region.
[00:31:07.310]So with that in mind, for preventing
[00:31:11.137]and especially pathogenic bacteria,
[00:31:12.350]they really like that neutral zone.
[00:31:15.190]So if we're trying to prevent them from growing,
[00:31:17.430]we can acidify our products.
[00:31:19.520]That's why fruit juices, salsas,
[00:31:25.115]they tend to last longer or they tend to be a safer product
[00:31:29.320]because of that acidity.
[00:31:34.490]So microorganisms may be coming to your product
[00:31:38.413]from the soil, from the water that you're using.
[00:31:41.970]The source is basically the environment.
[00:31:43.650]They're coming from everywhere.
[00:31:46.090]The question is what are we gonna do about it
[00:31:48.680]in terms of preventing them from becoming an issue.
[00:31:52.539]There are some microorganisms that I mentioned
[00:31:54.010]at the beginning of this lecture that they are good,
[00:31:56.490]we actually want them there.
[00:31:58.010]Some, not so much and some, definitely not.
[00:32:02.430]So the good ones are the ones
[00:32:03.760]that we're gonna add to foods on purpose.
[00:32:06.420]So we're gonna add them to ferment the products
[00:32:09.060]to develop flavors and textures.
[00:32:11.490]Examples would be when we add bacteria to milk
[00:32:14.890]to make yogurt or add bacteria to milk to make cheese
[00:32:19.230]or we may add bacteria to a batter to make sourdough bread.
[00:32:25.260]So there's several products that we make that are fermented.
[00:32:30.100]They're produced with the help of bacteria.
[00:32:34.690]The bad ones are the ones that are gonna change the food
[00:32:38.459]and cause them to go bad or spoiled
[00:32:40.270]but they're not gonna cause any sickness
[00:32:42.420]but it's not pleasant.
[00:32:43.660]You don't want anybody to buy your food
[00:32:45.700]or come to your establishment and face product
[00:32:50.758]that is not ideal, that the quality is not its best.
[00:32:54.900]So we don't want that.
[00:32:58.231]It's not very good.
[00:32:59.249]And the other ones are the ones
[00:33:00.247]that are actually gonna cause sickness.
[00:33:01.755]These ones are the pathogens.
[00:33:03.250]They are the ones that will cause foodborne illnesses
[00:33:06.100]and the illnesses can vary from very mild
[00:33:09.620]to life threatening and here we have a list,
[00:33:12.510]probably not exhaustive but a pretty good comprehensive list
[00:33:16.670]of microorganisms that can be associated with food
[00:33:20.180]and can cause sickness.
[00:33:25.670]As I mentioned at the very beginning,
[00:33:27.700]when we're talking about bacteria, virus,
[00:33:30.470]we can see here that in the US,
[00:33:33.500]on an annual basis, most of the cases comes from virus.
[00:33:38.650]58% of foodborne illnesses are associated with virus
[00:33:43.115]and the way that we prevent them from happening
[00:33:45.195]is through personal hygiene and sanitation
[00:33:46.730]and we're gonna talk a little bit about later
[00:33:49.720]in our next lecture but nonetheless,
[00:33:52.310]there is a group here of pathogens
[00:33:55.180]that contribute to all the illnesses
[00:33:58.900]and what is important about that is the number of deaths
[00:34:04.030]and hospitalizations that it causes.
[00:34:06.443]So we pay attention to them because they are highly,
[00:34:13.570]like the illnesses that they cause are life threatening
[00:34:19.290]and we're very much concerned about it.
[00:34:21.620]One organism that is not listed here because
[00:34:25.447]of the due diligence of the industry
[00:34:30.183]and the good work of health inspectors
[00:34:32.411]and government inspectors, it doesn't show up
[00:34:35.910]on the statistics is the one caused clostridium botulinum
[00:34:39.840]and we want to keep it that way
[00:34:41.250]because that one, when it happens,
[00:34:43.140]mortality rate, extremely high.
[00:34:45.580]So when you have an outbreak of botulinum or botulism
[00:34:49.400]which is the disease caused by the toxin botulinum,
[00:34:53.642]things do not look very good.
[00:34:56.570]So we try to keep them out of the statistics
[00:34:58.900]and we're doing a good job and the way that we do that
[00:35:01.560]is by training the industry
[00:35:03.870]and talking to the industry and providing information
[00:35:08.930]and having systems in place that prevent that organism
[00:35:14.130]So clostridium botulinum is mostly associated
[00:35:17.690]with two types of processes.
[00:35:19.470]One is canned goods and if you work in a facility
[00:35:23.470]that actually produces canned goods,
[00:35:25.920]employees of that facility are required by the FDA
[00:35:28.970]to go through a school.
[00:35:30.960]It varies from three to five days of education
[00:35:34.050]associated with how to prevent
[00:35:36.529]that organism from being an issue.
[00:35:37.910]It's a big deal.
[00:35:41.590]The University of Nebraska offers
[00:35:42.806]that training a few times a year.
[00:35:43.639]We always have a classroom full of people taking
[00:35:46.517]and it's very important and it's one of the main tools
[00:35:50.450]that we have used over the years to prevent
[00:35:53.360]that organism from being an issue.
[00:35:55.440]It's by educating and making sure that the industry
[00:35:57.820]is having things in place, controls in place,
[00:36:02.006]that prevent them from becoming a problem.
[00:36:05.320]Guess what is the other area that this can become an issue?
[00:36:13.841]Reduced oxygen packaging.
[00:36:18.304]And we're gonna cover a little bit more of the organism
[00:36:21.000]or characteristic of this organism
[00:36:22.690]in the next few slides but basically,
[00:36:24.930]it's an organism that produces the spores
[00:36:28.341]so cooking your product is not gonna necessarily kill it
[00:36:31.125]and then you package it in an environment
[00:36:32.740]that has no oxygen, clostridium botulinum is an
[00:36:36.700]anaerobic organism so you're creating the perfect place
[00:36:39.500]for it to grow but there's hope.
[00:36:42.480]We still can make safe products, we just need to learn how.
[00:36:45.700]So that's what we're here for.
[00:36:49.900]So here it is, clostridium botulinum.
[00:36:53.304]It's an anaerobic microorganism
[00:36:55.248]so it does not like oxygen.
[00:36:56.081]Every time you remove oxygen,
[00:36:57.740]you're making it perfect for it to grow.
[00:37:00.540]The spores are heat resistant
[00:37:01.990]so we're not gonna kill it by cooking
[00:37:04.190]and some strains are psychrotrophic
[00:37:05.984]meaning even putting it in the fridge
[00:37:08.850]may or may not prevent it from growing.
[00:37:11.250]For the most part, it is but there's one particular strain
[00:37:15.170]that can grow under refrigerated temperatures
[00:37:18.430]so we need to limit the time.
[00:37:20.050]We just need to make sure that yes,
[00:37:21.700]we will refrigerate but we're not gonna refrigerate forever
[00:37:24.267]and that's what our regulations are based on.
[00:37:27.520]So when we get to the point of looking at the regulations
[00:37:29.909]that you're gonna see what do you need to do
[00:37:32.640]to keep this food safe.
[00:37:34.380]It's totally scientific based, you know?
[00:37:38.740]It's because of the characteristics of the organism,
[00:37:41.480]because of how much we know about it,
[00:37:43.340]we have found ways of preventing it
[00:37:45.950]from being an issue so as long as you follow those rules,
[00:37:49.840]all the product that you make should be safe.
[00:37:54.000]They do not grow or produce toxins below 4.5
[00:37:56.970]so if you're dealing with acidified products,
[00:37:59.560]then you have an extra caution, an extra safety layer.
[00:38:03.890]But if your product is closer to neutral
[00:38:06.470]which a lot of the foods that are served in restaurants are,
[00:38:09.730]then we need to rely a lot on that temperature control,
[00:38:13.770]the refrigerated control.
[00:38:15.940]The toxin that's produced by this microorganism
[00:38:19.877]is called botulinum, botulinum toxin,
[00:38:24.597]and it causes a disease that's called botulism
[00:38:30.336]and it's the most powerful toxin
[00:38:31.169]that is known by humans.
[00:38:34.070]Very, very, very little amounts can kill a human being
[00:38:39.630]so we want to make sure that we prevent that from happening.
[00:38:43.160]The symptoms of this disease is dryness of the mouth
[00:38:46.710]and throat, double vision, it is a neurotoxin
[00:38:51.130]so it's gonna affect your nervous system
[00:38:54.496]like your control of your body so you can go into
[00:38:59.170]a state of progressive paralysis of your muscles
[00:39:02.260]that will then induce cardiac and pulmonary failure
[00:39:07.120]so basically your heart can't pump anymore,
[00:39:09.830]your lungs can't expand and compress anymore,
[00:39:12.770]you have no control over those
[00:39:15.515]because of this type of toxin.
[00:39:17.670]The mortality rate is extremely high as you can,
[00:39:20.070]30 to 60% of the people depending upon the toxin,
[00:39:24.587]the strain that made the toxin,
[00:39:26.856]depending upon the dose that the person ingested.
[00:39:33.060]In some outbreaks, 60% of the people that were affected
[00:39:37.030]didn't make it so it's a big deal
[00:39:38.717]and that's why we want to make sure
[00:39:40.580]that we have the means in place
[00:39:43.653]to prevent that from happening.
[00:39:45.733]Associated with ROP products, domestic canning,
[00:39:47.570]occasionally with commercial canning
[00:39:50.440]but the number of outbreaks is very low
[00:39:54.990]and we want to keep it that way.
[00:39:57.915]Listeria, it's another organism.
[00:39:59.060]Those are the only two that we're gonna talk about today,
[00:40:01.275]clostridium and listeria and the reason why is because
[00:40:03.620]clostridium, like I said, can survive the cooking.
[00:40:07.890]The spores can survive the cooking
[00:40:10.459]and they don't like oxygen so they grow
[00:40:13.915]inside of the bag.
[00:40:15.493]Listeria is of concern because it's a vegetative
[00:40:19.010]anaerobic organism, meaning that it may grow
[00:40:22.310]inside of your bag as well and it's psychrotophic.
[00:40:26.075]It really likes those low temperatures so again,
[00:40:28.736]temperature and time are gonna be your control.
[00:40:31.570]We can keep it refrigerated but not forever.
[00:40:35.610]And there's only one species of this bacteria
[00:40:37.843]that is associated with pathogenicity in humans,
[00:40:40.750]high mortality rate, 20 to 30%,
[00:40:43.970]and it's the only organism that we know
[00:40:46.277]associated with food that can cross the placenta barrier.
[00:40:51.380]That's a big deal for pregnant women.
[00:40:55.400]If they come into contact with this organism,
[00:40:57.797]they get infected with this organism,
[00:40:59.352]they can cause tumor and other issues,
[00:41:03.340]even lead to an abortion or a stupor of that
[00:41:12.219]so it's a big deal.
[00:41:14.610]The symptoms for a healthy adult would be flu-like disease
[00:41:20.150]but if you are immune compromised or if you're pregnant,
[00:41:23.717]then the risks and the issues increase.
[00:41:27.350]Incubation period, it might take two to five weeks
[00:41:30.190]for you to actually develop the disease
[00:41:31.580]after ingesting a food that is contaminated
[00:41:34.050]and they are associated with meats, dairy products,
[00:41:37.701]a lot of refrigerated products as you can see
[00:41:39.030]because it has that ability to grow under refrigeration.
[00:41:43.340]In some of those products, we do store using ROP
[00:41:48.010]so that's the reason.
[00:41:49.360]So if you look at those two organisms
[00:41:52.080]that we are focusing on here today,
[00:41:54.400]there are things that we can use to prevent
[00:41:57.610]them from growing in the food.
[00:41:58.860]If we have an ability to change the pH,
[00:42:01.360]if we can drop the pH of the product to below 4.4,
[00:42:07.424]we would be able to prevent them but if acidifying
[00:42:08.870]our product is not an option,
[00:42:11.730]you could reduce the water activity.
[00:42:14.944]You could reduce the water activity below 0.92, say 0.9,
[00:42:19.960]you would prevent them from growing but again,
[00:42:22.843]that may not be an option if you're talking about
[00:42:25.925]foods that we serve again in a restaurant setting,
[00:42:30.920]most of the times they're high water activity
[00:42:34.059]even though you may not think of because
[00:42:36.124]they might be in a solid form,
[00:42:38.060]there's a lot of water inside that's available.
[00:42:41.200]Salt can help or temperature for growth.
[00:42:44.850]So for the ROP products, this is gonna be a big thing.
[00:42:48.280]We're gonna rely a lot on that
[00:42:51.330]so how are we gonna control the hazards?
[00:42:54.208]That's the most important.
[00:42:55.227]So I'm kind of just preparing you to understand
[00:42:57.080]how we control the hazards.
[00:42:58.800]All that we discussed so far was why
[00:43:02.260]these parameters are important.
[00:43:04.230]So for ROP, we could be talking about a controlled
[00:43:09.130]atmosphere where we may have low amounts of oxygen.
[00:43:14.100]We could have a modified atmosphere
[00:43:16.200]where we have replacement of oxygen
[00:43:19.000]with a different gas or we could have vacuum packaging
[00:43:22.100]where all gasses are removed so then
[00:43:25.400]I ask you what all this has in common?
[00:43:32.720]Anaerobic environment, yes.
[00:43:35.030]So what do we do then?
[00:43:38.386]Well, to control the hazard,
[00:43:39.510]we're gonna have to reduce the temperature
[00:43:42.747]but we can't keep it at reduced temperature forever
[00:43:44.610]because some of these organisms may still be able to grow.
[00:43:47.380]Remember listeria is a psychrotrophic.
[00:43:49.890]In some cases, we may have to freeze
[00:43:52.230]because in some products that we know are associated
[00:43:55.230]with those strains of clostridium
[00:43:57.550]that can grow under refrigeration,
[00:43:59.750]we might be putting those products in the freezer.
[00:44:02.400]So for some products, you're required to keep it frozen.
[00:44:05.470]Some products you could freeze
[00:44:07.670]but you could also keep it refrigerated
[00:44:10.140]so for some products, you have an option,
[00:44:12.220]some you must freeze.
[00:44:13.970]Fish is an example that needs to be maintained frozen
[00:44:18.090]at all times just to kind of start giving you examples.
[00:44:22.520]Cook chill process, you might have seen this slide today
[00:44:27.140]but basically you are cooking
[00:44:29.150]and then you're putting in a bag and then you're sealing it
[00:44:32.470]and then you are gonna chill fast
[00:44:35.872]and then you're gonna store and then eventually reheat
[00:44:39.090]so how we're gonna control hazards during this process
[00:44:43.897]so if that's what you're doing,
[00:44:45.294]well we're gonna use the cooking temperature
[00:44:47.830]to kill vegetative cells, right?
[00:44:48.980]Another point of control is that rapid chilling.
[00:44:53.157]Spores of bacteria will tend to replicate themselves
[00:45:00.990]faster or germinate faster at warmer temperatures
[00:45:04.600]so if we can cool chilled products very fast,
[00:45:09.440]we are reducing the amount of time
[00:45:11.710]that they are seeing into that warm temperature zone
[00:45:16.100]and we are preventing those spores from germinating.
[00:45:20.517]So that's why you have to cool your products very quickly
[00:45:23.340]and anybody doing cook and chill in the group?
[00:45:28.020]For those that do, you would have a chill curve
[00:45:32.330]and we're gonna have some handouts
[00:45:35.547]that we're gonna pass to you and you can take it along.
[00:45:37.685]It's gonna tell you how much time you have
[00:45:40.870]to reduce the temperature of the product from 135
[00:45:45.210]Fahrenheit to 120 to 80 to 30 to then be able
[00:45:50.340]to store at other refrigerated temperatures
[00:45:52.300]so you need to hit those marks to make sure
[00:45:55.610]that the product is maintained safely because
[00:45:57.870]you want to make sure that you drop that temperature
[00:45:59.920]as fast as possible so that's one measure of control
[00:46:03.090]for this type of process and then a limited refrigeration
[00:46:06.992]because we discussed about it.
[00:46:09.830]Eventually, they might be able to grow.
[00:46:12.860]Slowly, they might be able to grow
[00:46:14.400]so we don't want that to happen
[00:46:17.530]so we're gonna limit the time of refrigeration
[00:46:20.730]or we will freeze that product.
[00:46:23.816]If you're doing sous vide,
[00:46:26.380]you're kind of flipping the chart a little bit
[00:46:29.279]because you're gonna now prepare the food, bag it,
[00:46:31.457]and then cook and then you're gonna chill and store
[00:46:34.890]and just similarly, the cooking step
[00:46:38.456]is gonna be where we're gonna kill the pathogens
[00:46:42.370]and then the chilling, we're gonna do it as fast as we can
[00:46:45.140]to pass through that hot warm zone
[00:46:48.660]and prevent the spores that survive the cooking
[00:46:52.230]from germinating and then we're gonna put it under
[00:46:55.330]refrigeration so those spores remain spores
[00:46:58.860]and we're gonna keep it for a limited amount of time.
[00:47:01.602]So for ROP, how we're gonna control the hazards.
[00:47:05.140]We're gonna cook, we're gonna rapid chill,
[00:47:07.550]we're gonna keep it refrigerated
[00:47:09.290]for a limited amount of time or we're gonna freeze it.
[00:47:13.399]Any questions about this?
[00:47:16.550]What is rapid chill?
[00:47:20.625]Do you have the cards with you, Ben,
[00:47:22.225]so we can pass around?
[00:47:24.900]He's gonna grab it and then we have a curve,
[00:47:27.761]we have chart that will show you
[00:47:29.783]exactly how much time you have
[00:47:31.105]and it's like two hours to go from 135 to,
[00:47:34.411]it's shown in the curve.
[00:47:37.868]The curve, it's actually from the food code and from USDA
[00:47:43.921]so we have enough there.
[00:47:47.886]So we'll pass that around and you can take that home.
[00:47:53.620]Hopefully that will answer your question.
[00:47:58.180]So there's basically two steps?
[00:48:00.679]There's different steps.
[00:48:03.140]There are different possibilities.
[00:48:07.290]So as you can see there, if you're gonna store
[00:48:09.601]for seven days, then you have one curve to meet.
[00:48:14.230]If you're gonna store for longer,
[00:48:15.630]then you have another curve that you need to meet.
[00:48:18.520]So depending upon how you want to store it afterwards
[00:48:22.800]but nonetheless, you need to go down from 135 to 70
[00:48:26.500]in two hours.
[00:48:27.800]Then you have another four hours to go from 70 to 41
[00:48:34.050]so in other words, you can't exceed six hours
[00:48:38.220]to go down from 135 to 41 and then you can keep it
[00:48:42.010]refrigerated for seven days.
[00:48:44.740]If you want to freeze it, you need to keep cooling it
[00:48:46.460]and you have a fair amount of time, up to 48 hours,
[00:48:52.840]to get it down to 34 total time.
[00:48:54.710]And then it's safe with those things.
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