-: So we have seen this graphic up here today already
in one of our previous lectures and for this lecture,
we're gonna focus our attention on the last block here.
For safety concerns, we're gonna talk
a little bit about the microbiology
and the microorganisms that might be associated
with these products and what can we do to prevent them
from becoming an issue, from becoming a hazard,
for a consumer in the food
and we're also gonna talk a little bit about sanitation.
That's our last lecture.
So microorganisms are present in foods naturally.
That's just the nature of the world that we live in.
Nothing that we eat is necessarily sterile
unless you are purposefully being fed a diet
that's prepared for you for whatever reason.
If you're sick in the hospital then yeah,
maybe you might be fed something that was more processed
to be sterile but in general,
the foods in the environment that we live
has a lot of microorganisms and it's just normal
to encounter them in our daily lives.
But raw foods will contain microorganisms and basically,
part of our job is try to prevent them
from growing out of control and spoiling the products
or becoming a food safety hazard for the consumers
so they're there and some of them are good,
some of them we want to be there
because they might transform our product
in microorganism ways and things that are of our interest
and sometimes they are there
and they might spoil the product
or they might cause sickness
and those are the situations that
we want to prevent from happening.
The microorganisms that we will be discussing today
include molds, yeast, bacteria, and viruses
and we're gonna give a little bit of introduction
to each of them so you can better understand
how they may be associated with the foods,
how they grow, and then what can we do to control them
specifically when we talk about reduced oxygen packages.
So molds are multicellular organisms
meaning that they have several cells
that make up an organism just like us.
They reproduce themselves by
fruiting bodies that we care spores.
I like to compare them to plants
because they have these spores, they kinda work like seeds
so they produce them and then they can be spread with air
within and they can go places and they can land
in the surface of food products or equipment
and if there's any moisture, any nutrients there,
they can grow and start a new organism and from there,
they produce, they grow and multiply themselves
to the point that we can actually see.
Eventually, you may see a piece of bread be moldy
or fruits and vegetables get moldy
and they're larger than bacteria and yeasts
if we look at them under the microscope,
you'd be able to visualize them with less magnification
but in general, we can only see them if they grow enough
in a product to make a colony
and by the time you can actually see,
there's millions of them there.
They're widely distributed in the soil, in the air,
and they'll survive in many substances.
They don't need much to grow.
Just a little bit of moisture and some source of light.
So you can even see them growing in cardboard boxes,
drywall, they don't need a lot of nutrients.
Give them the right conditions, they'll grow anywhere.
And they're more tolerant to cold than heat.
What this means is that for the food environment,
we can kill them fairly easy if we heat up our foods
but it will spoil things that we put in the refrigerator
which kind of makes sense, right?
Cheeses, products that you usually put in the refrigerator,
they might eventually get moldy.
Yeasts are unicellular so now we're talking about
an organism, the whole organism is one cell.
They're smaller than molds but larger than a bacteria
when we're looking at them under the microscope
and then they'll reproduce themselves by budding,
that's what we call it.
And basically what it is, it's a mother cell.
It's gonna produce a daughter cell that's attached to it.
So you can see here in this picture
that you have the mother cell
and then it starts producing a daughter cell on the side
and once this little daughter cell
kinda has everything that it needs to survive on its own,
it gets detached from the mother cell
and becomes a new organism.
So one organism becomes two, two might become four,
and that's how they reproduce themselves
and we microbiologists actually call that growth
so when we say oh, the bacteria is growing,
it doesn't mean that it's actually growing in size.
It's multiplying itself and we talk a lot about
how we might prevent bacteria growth,
that's preventing them from multiplying themselves.
It's widely found in nature,
associated with liquid foods that have high sugar and acid.
So if you have juices, sometimes that's the bacteria
that might be spoil, or I'm sorry,
the microorganism that might be spoiling that juice
in the refrigerator or jams and jellies in the refrigerator
that might be spoiled by this type of microorganism.
Then we come to bacteria which is the most
important and troublesome of them because
they are the ones that can actually cause sickness.
They can cause foodborne illnesses.
They can produce enzymes that will spoil the product.
Because these microorganisms,
the way that they feed themselves
is by sending out all of their enzymes
out in the environment so the enzymes
can do the digestive job for them
and then they can absorb simple nutrients.
They're not like us.
We ingest the food and then our stomach
will do that digestion for us.
They have to actually do that in the food
so they send out the enzymes
and that's when our products are changing color,
changing flavor, because things are literally
being digested or changed by those enzymes
and that's just part of how they are feeding themselves.
In that process they may also send out toxins.
It's just part of how they grow, multiply themselves,
and things that they're producing as part of that process
and those toxins can cause illnesses
so that's when we encounter with intoxication,
food poisoning.
Single cells and microscopic.
Those are characteristics of this group of microorganisms
and they may come in several shapes and forms.
They might be like little rods
or they might be round and depending upon
how they're shaped, it might be part of their name
so there's some bacteria that we call basalis
because it's a rod shape.
Some bacteria we call it micrococcus
because they're little round shape.
So they come in many shapes and forms
and the last group that I wanted to discus with you
is the virus.
These are small infectious agents that replicate
only inside of living cells.
So they don't have necessarily the ability to grow in foods.
You're not gonna replicate in the food.
They might replicate in people and people may
contaminate the food and then the food becomes
a source of contamination to somebody else.
Somebody else will ingest that food and then will get sick.
We're gonna see it a little bit here
in the next couple slides.
It's the reason for the maturity of the foodborne illnesses
is transmitted by viruses.
While not inside of a cell,
it exists as a viral particle made of different parts.
Our slide here shows that there's a genetic material,
a protein coat, and an envelope.
In some cases, that might be part of that viral particle
and it's very, very small.
This type of microorganisms,
they're very, very small because they can actually even
move back a bacterium so they're much smaller than bacteria
and however they're very, very troublesome
and we'll see that in a couple slides.
Now we're gonna focus a little bit on the bacteria
and we're gonna discuss how they grow, multiply themselves,
and what are the factors that we can use to control
that process because they're the ones
that can cause disease the most
and they are the ones that we can actually control growth.
Virus and virus infection and foodborne illness
caused by virus are mostly prevented through sanitation
because they don't grow in the food.
The food is just a mechanism for them to spread themselves
to other people.
They go from one people to another
and we're gonna talk about sanitation in our next lecture.
So for this lecture, we're gonna focus on the bacteria
and how we can control.
So like I was saying, one microorganism or one bacteria
can multiply themselves into two
and the way that they do that is by
fission or division and we can see that in this slide.
So you have one organism that basically start
enlarging itself a little bit and doubling
everything that he has inside of that cell
to the point that it can become two separate cells.
When that happens, then a wall gets formed
between the cells and then each splits into two organisms
so from one, it goes to two, two goes to four,
and even though we might start kind of slow,
when you get to the thousands,
that multiplication factor goes up really fast.
So they can multiply themselves quite fast
because of this division that they are able to go through.
So under optimum conditions, this whole process
may take 20 to 30 minutes meaning that
if you have a food that is being exposed to a temperature,
foods that should be refrigerated but are not,
so now you are putting that food perhaps under
optimum conditions for this bacteria to grow,
they're gonna be multiplying themselves
every 20 to 30 minutes and you can put yourself
in a situation of high risk fairly quick.
This chart shows us that nonetheless,
different bacteria will have different times
that are required for them to divide themselves.
So some of them will have a generation time
and that's what we call.
Generation time is the amount of time for one bacteria
to split into two.
So that may take 20 minutes as you can see
so they can, in a matter of minutes or hours here,
they can multiply themselves fairly quickly
from maybe one individual all the way to 650 cells
if they do that every 20 minutes
and if they take 30 minutes or 40 minutes,
then they're not gonna grow as fast but they're still
gonna go through that process of multiplication.
There is among the bacteria one special group that's
of concern, much concern, for the food industry
in the food service because they can produce spores
and the reason they do it is because
the bacteria has this instinct for survival.
So when they are in an environment that they encounter
situations that they might sense that it's not going well
for them because they don't have enough nutrients,
the temperature may be too high or too cold,
whatever it is that's stressing them
and they're feeling that maybe they won't survive this,
they kind of pack all they're information,
they pack all they're DNA information
and everything that they need to multiply
and continue their species into this little capsule
inside of their bodies or their cells.
So here is a diagram that kind of shows that process.
So you have a vegetative cell.
This is how we call it a cell that's just growing
and multiplying.
We call them vegetative.
So you have a vegetative cell
that might have sensed that the environment
is not going their way in terms of nutrients
or temperature so the instincts for survivability
and they start forming that spore inside of the cell
and then when that spore gets ready to be released,
it will be released in the environment
and that may happen when that cell dies
so if the temperature or the nutrients
really get to the point that the bacteria would not survive,
the cell will die but that spore will survive
and bacteria has evolved in nature to point that
this spore here, it's a lot more resistant
to any environmental condition than the cell
that it was created by.
So it will survive much higher temperatures,
it will survive much dryer conditions,
it will survive sanitizers that we might use,
some chemicals.
We may be able to kill the vegetative cell
but we would not kill the spore.
And then when this spore is in an environment
that encounters conditions that
is good again for it to grow,
it will germinate into a vegetative cell again
and it will start that cycle of
growing and multiplying cells
so it's kind of like a survivability tool
that the bacteria has and why is it important?
It's because the conditions of cooking, chilling, freezing,
everything that we do in
the food industry except for canning
cannot kill this spore.
So if this bacteria is able to produce that spore,
it will survive our heating, it will survive our cooking,
and we need to use perhaps other tools,
other hurdles, other means to prevent them
from ever becoming a vegetative cell again
because if it hangs in the food in the form of spores,
it's not gonna make anybody sick
but if it becomes a vegetative cell
and starts growing again,
it might produce toxins and that's when problems arise.
So our job in the food industry,
for the most part of the products that we make
and most of the processes that we use,
food service and food industry,
we kill the vegetative cell and we do
everything in our power to prevent that spore
from ever becoming a vegetative cell again.
The only process that we do by nature
that actually will kill the spores is canning,
commercial canning.
You can do that home canning as well
as long as you do it well, using high enough temperatures.
But it's not the types of processes that we're necessarily
discussing here today.
So then it becomes the question how can I prevent bacteria
from multiplying itself fast or maybe
how can I prevent this spore from germinating
because that's how we're gonna,
those are the tools that we're gonna be using
to ensure that the food that we make is safe.
So this is basically our little toolbox
is what I call it.
It's the toolbox.
Those are all the factors that might affect,
in one way or another, growth and survival of bacteria
and other microorganisms in food
and depending upon the situation
and the process that we're doing,
we might be using one tool versus another
so when we're cooking or using temperature to kill it,
when we're doing acidified products like tomato sauces
and salsas or using the pH
in combination with mild temperatures.
So we can use different tools to control the growth
and the survivability of the organisms.
We're gonna go through each of them very briefly
just to kind of explain to you how they work.
So nutritional requirements.
Different bacteria will have different
nutritional requirements and sometimes,
you can use that to prevent them from growing in places.
However, when we talk about foods in general,
that's not a very good tool because
we do want our foods to be nutritional,
oblique with nutrients, we want it to be appealing.
So we're losing some of this,
nutrients may not be an option but I just wanted you
to know that different microorganisms
will have different nutrient requirements.
Some of them will require an environment
with more vitamins and minerals to be able to grow
and some other bacteria will grow in foods
that are less rich in those nutrients.
Moisture, this is a very good tool for us
because as I mentioned a little bit earlier today,
bacteria will only be able to feed themselves
if they can reach out to the environment
and have those nutrients come to them
and water is how things move around in our food products
and that's how the bacteria can actually reach
their nutrients.
So if we don't have any water available to move around
and carry things, the bacteria cannot
get a hold of those nutrients so if you take moisture out,
we can definitely reduce microbial grow.
Cases or examples of food processes that we do that,
can you think of anything?
Anything at all with any foods
that we preserve by removing water?
-: Maybe like sun dried tomatoes.
-: Absolutely.
Dried fruits, dried vegetables, and I'm sorry.
You remove water, yes, yep, during that process
and some others like we might not even think about.
Every time you bake something,
the final product has much less water
than the initial dough or batter.
So we remove water quite a bit when we process
or cook foods and that's how we help
or why our final products may last much longer
than your raw ingredient.
Water activity.
This is a concept that is very much related with moisture
but it has a twist to it so moisture is basically
the total amount of water that you have.
The amount of water in your product
you can define as the amount of moisture.
But some of this water may be busy
binding itself to components of your product,
some molecules that are part of that product,
and they're not necessarily available to move around.
Remember when I said that the bacteria needs water
moving around to be able to bring the nutrients to them?
So now if I remove or if I reduce
the amount of water that can move around,
the water might be there but if that water
is bound, stuck in place, we cannot help the bacteria.
So I can have a moist product
that doesn't help bacteria grow
because that water now, it's not able to move
or bring the nutrients to the bacteria anymore.
So the water that is available for the bacteria to grow,
that's what we call the water activity.
So the more water available to move around in food,
the higher is the water activity of the product
and that's influenced by the water binding capacity
of the ingredients.
Some ingredients are really good at binding with water.
Salt, sugar, would be the two main examples.
Products that have a lot of sugar in it,
they may have water and they may look moist
but that water is no good for bacteria to grow
because it's busy being bound and stuck by the sugar.
Let me see what I have here in my next slide.
There we go.
And different microorganisms will have
a different amount of water that they require
for their growth and that's the water activity
that we are talking about.
Some of them, as you can see like molds,
will require 0.75 water activity.
Yeasts will require more so right now,
I just want you to compare the numbers here.
Clostridium, salmonella, and staphylococcus aureus
will require quite a bit more water than yeast and mold.
What does it tell us?
It tells that first, bacteria,
it's a lot more picky in terms of where they grow.
They need a lot of free water,
otherwise they can't grow and the pathogenic bacteria
that needs the least amount needs 0.85.
So that number, it's very important in terms of food safety
because if not, you have a product that's below 0.85,
pathogen bacteria cannot grow anymore
so it becomes like a line that we draw
for food safety in terms of water available.
But you might be asking yourself where
this number is coming from, 0.75, 0.85, what does it mean?
So basically, the way that we measure water activity
is you use machines like tabletop machines
in the laboratory that actually
make this measurement for us.
It all depends on water, like pure water.
So if I had a glass of water
and I put a little bit of that water in my machine,
my machine's gonna tell me that the water activity
of that glass of water is one.
Everything else, every other product,
is gonna have less than one.
The more ingredients, the more components
I add to that glass of water,
the less water is free to move around
and my water activity starts being reduced.
So if I have water and I have milk,
water will be probably around one.
Water is gonna be one.
Milk is gonna be probably 0.99 or 0.98.
If I have now maybe another product
that it's a lot more, let me think, a milkshake.
Going from milk to a milkshake where you added
other ingredients, you might add some things
to make it thicker, you might have fruits and more sugar,
that will have a water activity that is even lower,
maybe in the range of 0.9 but still
is gonna be pretty high because that milkshake
will spoil fairly easily, wouldn't it,
if I don't put it in the refrigerator
or if I don't do anything with it.
So that's where the water activity is.
One thing that I always think is interesting is how
the water can be bound in the product and we don't realize
so if we were to compare and I don't think,
let me see here, yeah, I don't have a table
in this presentation but we can just talk about it
a little bit.
If I were to compare the amount of water activity
in different products, you would think that a piece of bread
for example because the way it presents itself,
it's a solid product, the amount of water activity
that we have in bread, believe it or not,
it's higher than the amount of water activity
that we would have in the jam that might spread
on top of the bread because that jam
has a lot of sugar and the water might be there,
might make your product very smooth and spreadable,
but it's not available for bacteria to grow
or for molds to grow so in a sense,
your bread would spoil faster than your jam
because the bread will have a higher water activity.
For the most part, depending upon
the recipe of the bread, of course.
But for the most part, if we just looked at bread,
a regular recipe of bread, compared to jam
which is then interesting because
you would perhaps expect to have more water activity
in the jam, right, because it's a spreadable product.
Okay so moving on, oxygen requirements.
The different bacteria will have different requirements.
Some of them will like oxygen.
They will require oxygen for them to grow just like us.
If you take oxygen out, what happens to us?
We die.
We're pretty much dead.
It won't take long.
I don't know if I can hold my breath for more than like
more than a minute and a half, I don't know.
Wouldn't even try.
But they work pretty quickly.
In the case of the bacteria, we may not kill them
because they're pretty resourceful.
They're just gonna sit quiet there and not grow
and then when you give oxygen back, they start growing.
They're better than us in that regard
'cause we would pretty much die but they will not die.
They will just sit quietly there in the product.
Some others don't like oxygen.
They are only gonna grow if you remove the oxygen
and in some cases, that's a big deal because
what are we here for today?
So there's bacteria that's gonna grow
exactly when you do that and that's our concern.
And different groups will behave differently
and some of them are vegetative.
That means that they don't care.
They will grow either way,
in the presence or absence of the oxygen.
Temperature is another characteristic.
Different bacteria will prefer different temperatures.
Some of them are adapted to grow at a higher temperature,
some at a more ambient temperature,
and some at refrigerated temperatures.
Why do we care?
Where do we keep a lot of our products
that we try to increase shelf life?
What do we do with it?
We refrigerate it.
Even when we refrigerate, we are preserving the product
and preventing all the ones, all the bacteria that
fits or falls into this part of the chart here
will be prevented from growing and that's great.
That gives us a lot more shelf life for our product
but there's this little group here that's still gonna grow
so that's why even under refrigerated conditions,
we have limits in time.
That's why very soon here,
we're gonna be talking about you keep it refrigerated
but no longer in a certain amount of time
because this group over here,
they kind of grow slow because the temperature,
it's not very favorable but slowly but surely,
they'll get there so give it enough time,
they'll become an issue, too.
So there's pathogenic bacteria that falls into
that category, listeria is one,
that they like growing under lower temperature conditions.
They're kind of slowly doing so
so they give us a little bit of time
so we can keep foods in the refrigerator
for a certain period but we can't keep them there
because even the refrigerator,
we're not gonna forever prevent it from growing
so that's the importance of keeping an eye on the time.
How long are you gonna keep things refrigerated?
And temperature, if we increase a temperature high enough
like cooking temperatures, then we're actually killing it.
Then finally, we're getting to the point of killing it,
not just prevent it from growth or inactivating them
but we're only gonna kill which ones,
vegetative or spores?
Vegetative.
Spores are gonna still sit there
and if you don't do something afterwards,
they may come back so that's the point
and the higher the temperature here,
that's what I want to show in this chart.
The higher the temperature, the faster we can kill
the bacteria so this is the population of bacteria.
By increasing the temperature here,
we can then reduce a lot amount of time that is required
for killing the bacteria.
pH, that's the degree of acidity or alkalinity
of the product.
Most food products, we can kind of see here in this chart.
Most food products are gonna be on the neutral
or even like slightly acidic to acidic
so we'll have milk here goes to neutral
and everything else that's kind of down from there
and yeast and molds will be able to grow at a lower pH
so they tend to spoil in growing products
that are in this area over here
while bacteria might like better this region.
So with that in mind, for preventing
and especially pathogenic bacteria,
they really like that neutral zone.
So if we're trying to prevent them from growing,
we can acidify our products.
That's why fruit juices, salsas,
they tend to last longer or they tend to be a safer product
because of that acidity.
So microorganisms may be coming to your product
from the soil, from the water that you're using.
The source is basically the environment.
They're coming from everywhere.
The question is what are we gonna do about it
in terms of preventing them from becoming an issue.
There are some microorganisms that I mentioned
at the beginning of this lecture that they are good,
we actually want them there.
Some, not so much and some, definitely not.
So the good ones are the ones
that we're gonna add to foods on purpose.
So we're gonna add them to ferment the products
to develop flavors and textures.
Examples would be when we add bacteria to milk
to make yogurt or add bacteria to milk to make cheese
or we may add bacteria to a batter to make sourdough bread.
So there's several products that we make that are fermented.
They're produced with the help of bacteria.
The bad ones are the ones that are gonna change the food
and cause them to go bad or spoiled
but they're not gonna cause any sickness
but it's not pleasant.
You don't want anybody to buy your food
or come to your establishment and face product
that is not ideal, that the quality is not its best.
So we don't want that.
It's not very good.
And the other ones are the ones
that are actually gonna cause sickness.
These ones are the pathogens.
They are the ones that will cause foodborne illnesses
and the illnesses can vary from very mild
to life threatening and here we have a list,
probably not exhaustive but a pretty good comprehensive list
of microorganisms that can be associated with food
and can cause sickness.
As I mentioned at the very beginning,
when we're talking about bacteria, virus,
we can see here that in the US,
on an annual basis, most of the cases comes from virus.
58% of foodborne illnesses are associated with virus
and the way that we prevent them from happening
is through personal hygiene and sanitation
and we're gonna talk a little bit about later
in our next lecture but nonetheless,
there is a group here of pathogens
that contribute to all the illnesses
and what is important about that is the number of deaths
and hospitalizations that it causes.
So we pay attention to them because they are highly,
like the illnesses that they cause are life threatening
and we're very much concerned about it.
One organism that is not listed here because
of the due diligence of the industry
and the good work of health inspectors
and government inspectors, it doesn't show up
on the statistics is the one caused clostridium botulinum
and we want to keep it that way
because that one, when it happens,
mortality rate, extremely high.
So when you have an outbreak of botulinum or botulism
which is the disease caused by the toxin botulinum,
things do not look very good.
So we try to keep them out of the statistics
and we're doing a good job and the way that we do that
is by training the industry
and talking to the industry and providing information
and having systems in place that prevent that organism
from revitalization.
So clostridium botulinum is mostly associated
with two types of processes.
One is canned goods and if you work in a facility
that actually produces canned goods,
employees of that facility are required by the FDA
to go through a school.
It varies from three to five days of education
associated with how to prevent
that organism from being an issue.
It's a big deal.
The University of Nebraska offers
that training a few times a year.
We always have a classroom full of people taking
and it's very important and it's one of the main tools
that we have used over the years to prevent
that organism from being an issue.
It's by educating and making sure that the industry
is having things in place, controls in place,
that prevent them from becoming a problem.
Guess what is the other area that this can become an issue?
Reduced oxygen packaging.
And we're gonna cover a little bit more of the organism
or characteristic of this organism
in the next few slides but basically,
it's an organism that produces the spores
so cooking your product is not gonna necessarily kill it
and then you package it in an environment
that has no oxygen, clostridium botulinum is an
anaerobic organism so you're creating the perfect place
for it to grow but there's hope.
We still can make safe products, we just need to learn how.
So that's what we're here for.
So here it is, clostridium botulinum.
It's an anaerobic microorganism
so it does not like oxygen.
Every time you remove oxygen,
you're making it perfect for it to grow.
The spores are heat resistant
so we're not gonna kill it by cooking
and some strains are psychrotrophic
meaning even putting it in the fridge
may or may not prevent it from growing.
For the most part, it is but there's one particular strain
that can grow under refrigerated temperatures
so we need to limit the time.
We just need to make sure that yes,
we will refrigerate but we're not gonna refrigerate forever
and that's what our regulations are based on.
So when we get to the point of looking at the regulations
that you're gonna see what do you need to do
to keep this food safe.
It's totally scientific based, you know?
It's because of the characteristics of the organism,
because of how much we know about it,
we have found ways of preventing it
from being an issue so as long as you follow those rules,
all the product that you make should be safe.
They do not grow or produce toxins below 4.5
so if you're dealing with acidified products,
then you have an extra caution, an extra safety layer.
But if your product is closer to neutral
which a lot of the foods that are served in restaurants are,
then we need to rely a lot on that temperature control,
the refrigerated control.
The toxin that's produced by this microorganism
is called botulinum, botulinum toxin,
and it causes a disease that's called botulism
and it's the most powerful toxin
that is known by humans.
Very, very, very little amounts can kill a human being
so we want to make sure that we prevent that from happening.
The symptoms of this disease is dryness of the mouth
and throat, double vision, it is a neurotoxin
so it's gonna affect your nervous system
like your control of your body so you can go into
a state of progressive paralysis of your muscles
that will then induce cardiac and pulmonary failure
so basically your heart can't pump anymore,
your lungs can't expand and compress anymore,
you have no control over those
because of this type of toxin.
The mortality rate is extremely high as you can,
30 to 60% of the people depending upon the toxin,
the strain that made the toxin,
depending upon the dose that the person ingested.
In some outbreaks, 60% of the people that were affected
didn't make it so it's a big deal
and that's why we want to make sure
that we have the means in place
to prevent that from happening.
Associated with ROP products, domestic canning,
occasionally with commercial canning
but the number of outbreaks is very low
and we want to keep it that way.
Listeria, it's another organism.
Those are the only two that we're gonna talk about today,
clostridium and listeria and the reason why is because
clostridium, like I said, can survive the cooking.
The spores can survive the cooking
and they don't like oxygen so they grow
inside of the bag.
Listeria is of concern because it's a vegetative
anaerobic organism, meaning that it may grow
inside of your bag as well and it's psychrotophic.
It really likes those low temperatures so again,
temperature and time are gonna be your control.
We can keep it refrigerated but not forever.
And there's only one species of this bacteria
that is associated with pathogenicity in humans,
high mortality rate, 20 to 30%,
and it's the only organism that we know
associated with food that can cross the placenta barrier.
That's a big deal for pregnant women.
If they come into contact with this organism,
they get infected with this organism,
they can cause tumor and other issues,
even lead to an abortion or a stupor of that
so it's a big deal.
The symptoms for a healthy adult would be flu-like disease
but if you are immune compromised or if you're pregnant,
then the risks and the issues increase.
Incubation period, it might take two to five weeks
for you to actually develop the disease
after ingesting a food that is contaminated
and they are associated with meats, dairy products,
a lot of refrigerated products as you can see
because it has that ability to grow under refrigeration.
In some of those products, we do store using ROP
so that's the reason.
So if you look at those two organisms
that we are focusing on here today,
there are things that we can use to prevent
them from growing in the food.
If we have an ability to change the pH,
if we can drop the pH of the product to below 4.4,
we would be able to prevent them but if acidifying
our product is not an option,
you could reduce the water activity.
You could reduce the water activity below 0.92, say 0.9,
you would prevent them from growing but again,
that may not be an option if you're talking about
foods that we serve again in a restaurant setting,
most of the times they're high water activity
even though you may not think of because
they might be in a solid form,
there's a lot of water inside that's available.
Salt can help or temperature for growth.
So for the ROP products, this is gonna be a big thing.
We're gonna rely a lot on that
so how are we gonna control the hazards?
That's the most important.
So I'm kind of just preparing you to understand
how we control the hazards.
All that we discussed so far was why
these parameters are important.
So for ROP, we could be talking about a controlled
atmosphere where we may have low amounts of oxygen.
We could have a modified atmosphere
where we have replacement of oxygen
with a different gas or we could have vacuum packaging
where all gasses are removed so then
I ask you what all this has in common?
Anaerobic environment, yes.
So what do we do then?
Well, to control the hazard,
we're gonna have to reduce the temperature
but we can't keep it at reduced temperature forever
because some of these organisms may still be able to grow.
Remember listeria is a psychrotrophic.
In some cases, we may have to freeze
because in some products that we know are associated
with those strains of clostridium
that can grow under refrigeration,
we might be putting those products in the freezer.
So for some products, you're required to keep it frozen.
Some products you could freeze
but you could also keep it refrigerated
so for some products, you have an option,
some you must freeze.
Fish is an example that needs to be maintained frozen
at all times just to kind of start giving you examples.
Cook chill process, you might have seen this slide today
but basically you are cooking
and then you're putting in a bag and then you're sealing it
and then you are gonna chill fast
and then you're gonna store and then eventually reheat
so how we're gonna control hazards during this process
so if that's what you're doing,
well we're gonna use the cooking temperature
to kill vegetative cells, right?
Another point of control is that rapid chilling.
Spores of bacteria will tend to replicate themselves
faster or germinate faster at warmer temperatures
so if we can cool chilled products very fast,
we are reducing the amount of time
that they are seeing into that warm temperature zone
and we are preventing those spores from germinating.
So that's why you have to cool your products very quickly
and anybody doing cook and chill in the group?
For those that do, you would have a chill curve
and we're gonna have some handouts
that we're gonna pass to you and you can take it along.
It's gonna tell you how much time you have
to reduce the temperature of the product from 135
Fahrenheit to 120 to 80 to 30 to then be able
to store at other refrigerated temperatures
so you need to hit those marks to make sure
that the product is maintained safely because
you want to make sure that you drop that temperature
as fast as possible so that's one measure of control
for this type of process and then a limited refrigeration
because we discussed about it.
Eventually, they might be able to grow.
Slowly, they might be able to grow
so we don't want that to happen
so we're gonna limit the time of refrigeration
or we will freeze that product.
If you're doing sous vide,
you're kind of flipping the chart a little bit
because you're gonna now prepare the food, bag it,
and then cook and then you're gonna chill and store
and just similarly, the cooking step
is gonna be where we're gonna kill the pathogens
and then the chilling, we're gonna do it as fast as we can
to pass through that hot warm zone
and prevent the spores that survive the cooking
from germinating and then we're gonna put it under
refrigeration so those spores remain spores
and we're gonna keep it for a limited amount of time.
So for ROP, how we're gonna control the hazards.
We're gonna cook, we're gonna rapid chill,
we're gonna keep it refrigerated
for a limited amount of time or we're gonna freeze it.
Any questions about this?
Student: What is rapid chill?
-: Do you have the cards with you, Ben,
so we can pass around?
He's gonna grab it and then we have a curve,
we have chart that will show you
exactly how much time you have
and it's like two hours to go from 135 to,
it's shown in the curve.
The curve, it's actually from the food code and from USDA
so we have enough there.
So we'll pass that around and you can take that home.
Hopefully that will answer your question.
Student: So there's basically two steps?
-: There's different steps.
There are different possibilities.
So as you can see there, if you're gonna store
for seven days, then you have one curve to meet.
If you're gonna store for longer,
then you have another curve that you need to meet.
So depending upon how you want to store it afterwards
but nonetheless, you need to go down from 135 to 70
in two hours.
Then you have another four hours to go from 70 to 41
so in other words, you can't exceed six hours
to go down from 135 to 41 and then you can keep it
refrigerated for seven days.
If you want to freeze it, you need to keep cooling it
and you have a fair amount of time, up to 48 hours,
to get it down to 34 total time.
And then it's safe with those things.