Preventing Cross-Contamination and Using Thermometers Correctly

[Music] hey chef bates here again we are gonna go through chapter four the flow of food

out of servsafe this is the introduction to this very important topic uh today we're just going to talk about

preventing cross-contamination and how to use thermometers correctly to keep food safe you have to

apply what you learn in the servsafe program throughout the flow food this is the path food takes through the

operation it begins when we buy it and it ends when we serve it detailed practices for each phase are covered in

later chapters but we as restaurant professionals are responsible for the safety of the food

at every point in the flow and a lot of stuff

can potentially happen to it for example a frozen food might be safe when it leaves the processor's plant however

on the way to the supplier's warehouse the food might thaw once in your operation that food

might not get stored correctly or it might not be cooked to the correct internal temperature

these mistakes can add up and cause a foodborne illness that's why it is important to understand

how to prevent time temperature abuse and how to prevent cross-contamination to keep food safe through the flow of

food you've got to prevent cross-contamination and you've got to prevent time temperature abuse

pathogens they can move around easily in any restaurant any place where food is made

they can move around pretty easily they can be spread from food or unwashed hands to prep areas equipment

utensils or other food cross-contamination can happen at almost any point

in the flow of food when you know how and where it can happen it is fairly easy to prevent

cross-contamination the most basic way is to keep raw and ready-to-eat food away from each

other most foodborne illnesses happen because tcs food has been

time temperature abused remember tcs food has been time temperature abused anytime it remains between 41 degrees

fahrenheit in 135 degrees fahrenheit that's the temperature danger zone we call it that because pathogens grow

pretty quick there but most pathogens grow much faster between

70 degrees fahrenheit and 125 degrees fahrenheit check out the little red uh box over

here where it says pathogens grow rapidly if the temperature danger zone is 41 to 135

70 to 125 is like the super danger zone food is being temperature abused whenever it's handled in the following

ways it's cooked to the wrong internal temperature it's held at the wrong

temperature or it's cooled or reheated incorrectly the longer the food stays in the temperature

danger zone the more time pathogens have to grow to keep food safe you must reduce the time it spends

in this temperature range if food is held in this range for four or more hours you must throw it out

four or more hours throw it away four or more hours four sheesh remember that so how do you

prevent cross-contamination from happening well we already have talked about some ways

here's some more practical ways are hey why don't we buy food that doesn't require us to prep it

or even really touch it you can buy pre-cooked chicken breast you can buy pre-chopped lettuce and uh

you through a company like cisco you can get almost everything that you need to

uh make pre-made it's not especially great and you're certainly not a scratch kitchen

but you're a very safe kitchen but if you are going to make everything yourself

and you've only got one big prep table for different types of food it's very important that you prep your raw meat

fish and poultry at a different time than you're ready to eat food you've got to clean and sanitize

your work surfaces and utensils between each type of food you're preparing also very important

if you're preparing ready-to-eat food and raw food do the ready-to-eat food first and the

raw food second that'll definitely reduce the chance of cross-contamination

so throughout this process you're going to have to teach the people that work for you

which food items have to be checked how often and who is responsible for it you got to

make sure your food handlers understand what to do how to do it and why it is so important

and along the way obviously you need to make sure that all of your employees have the correct kind of thermometers

on them you should give them their own have them use their timers and prep areas to check how

long food is in the temperature danger zone have them clean and sanitize their own

probe thermometers so that they're able to keep track they're able to monitor

time and temperature while they're doing this really wise idea is to have your food

handlers record those temperatures they're taking regularly make sure they write down when

the temperatures were taken there are simple forms online for this you can post them on clipboards

outside of coolers and freezers near prep areas next to cooking and holding equipment

you want to have some procedures in place that are going to limit the time that tcs food spends in the temperature

danger zone here's an example let's say that you are prepping cases and cases in cases of raw chicken

but you know that each case takes your worker about one hour to prep don't allow them to take out three cases

at a time put in place a policy that only one case can come out at a time

that's the way that you limit the that's the way that you limit the amount of time that food will spend in

the temperature danger zone and the last thing that we can do to prevent cross-contamination is make sure

that everybody knows what to do if time and temperature standards are not met for example if you

hold soup on a steam table and its temperature falls below 135 degrees fahrenheit

after two hours you could reheat it to the correct temperature or you might throw it out but if it was there for

four hours it spent four hours in the temperature danger zone the only thing you could do is throw it

away make sure everybody knows the rules and you don't have to worry about what they

do to keep food safe you must control the amount of time it spends

and the temperature danger zone this requires monitoring as we've said and the most important tool you have to

monitor temperature is the thermometer there are three types of thermometers that we're going to talk about because

they are the ones most commonly used in restaurants bi-metallic stemmed thermometers

digital thermometers like thermocouples and thermostars and infrared thermometers

a biometallic stem thermometer we'll talk about that one first because it's the one we use the most often

it can check temperatures from 0 degrees to 220 degrees fahrenheit it's really helpful for checking

temperatures during the flow of food for example you can use it to check food temperatures during

receiving and you can also use it to check food temperatures in a hot or cold holding unit like a buffet table a

bi-metallic stem thermometer measures temperature through its stem when checking temperatures you want

to insert the stem into the food all the way up to the dimple you've got to do this because the

sensing area of the thermometer goes from the tip of the stem to the dipple

it's great for checking large and thick food however it's not that practical for thin

foods such as hamburger patties because a hamburger patty is not as thick as

the sensing area of the bimetallic stem thermometer so let's say that you are purchasing

some bimetallic stem thermometers for your restaurant they need to have three features they need to have the

calibration nut which is just underneath the indicator head that's how you adjust the thermometer

to make it accurate it needs to have easy to read markings on that indicator head

because clear markings reduce the chance that someone's going to misread the thermometer and get the wrong

temperature it's got to be scaled to two degree increments and it has to have a clear

dimple the little indentation on the stem that shows

the where the sensing area is where the temperature sensing area is so you don't want to buy metallic stem

thermometer because you like the fancy ones so you're going to get yourself a digital thermometer

you're going to be purchasing either a thermocouple or a thermostar those are the two types of digital

thermometers that are used in restaurant work and if you ever see a question on

surfsafe about a thermostore or a thermocouple just remember they're just talking about digital thermometers

using a fancy name the tools are really really similar the only difference between them is the technology inside

both are displaying temperature digitally both have a sensing area that's located on the

very very tip this means that you don't have to insert them all the way into food like you do with a bi-metallic stem

thermometer to get a correct reading makes them great for thin food and they

come with all kinds of cool different attachments they come with surface probes that are

used to check the temperature of flat surfaces like a griddle they have air probes that are air

attachments so that you can measure the temperature inside of a cooler or an oven

immersion probes for checking the temperature of liquids such as soups or sauces or frying oil and

penetration probes for actually checking food just like you would with a bi-metallic stem

thermometer the only difference is you can only have to use the tip so you can use them with very thin foods like

hamburger patties or fish fillets the next thermometer fun it's the laser gun everybody loves

the laser thermometers but they're only good for two things they're only good for surface

temperatures that's it they're only good for surface temperatures and surface temperatures of

food and surface temperatures of cooking equipment they aren't going to measure the interior temperature of food in

their they're you certainly can't use them to figure out how hot soup is

for those you would need an immersion probe thermometer or a bi-metallic stem thermometer right

but they are pretty cool and they're fun to work with there are a couple rules about them though

you want to hold the thermometer as close to the food or equipment as you can

without touching it you got to make sure there's nothing between the little laser and the food

so don't try to take a temperature reading through metal or certainly don't do it through

glass because the laser can bounce off the glass and shoot you in the eye and shoot your eye out always follow

manufacturer's directions while you're using a laser thermometer please that would be great

hey there's a couple more that we don't really use for food but they sure are fun

uh maximum registering thermometers are these cool tools we have one of these we use it to make sure that our dishwasher

the final rinse is hitting 180 degrees it only is going to tell you the highest temperature reach that's what it's good

for all you have to do is put this baby on the dish rack with the rest of the

dishes and it's going to display the highest temperature recorded during the dish cycle it's great for checking

the final rinse temperature of a dish washing machine another type of thing is maximum

registering tape does the exact same thing but it's disposable you just

take the little sticker and you put it on the outside of the dish rack and it's going to turn colors

if it gets to the right temperature so on this particular tape it has a little blue bar actually it

looks kind of purple and that bar is going to turn bright orange if the dishwasher final

rinse is going to hit 180 degrees that way we know we're safe the last specialty thermometer is called

a tti a time temperature indicator these are cool because

it's not just measuring temperature it's also measuring the length of time that that sticker stays at that

temperature so these are great they're attached to packaging by a lot of different suppliers

and the color change appears in the window if the food has been time temperature abused during

shipment or storage now the color change can't be reversed so they can't like cheat if you see it

on there you know that that food has not spent more than

one or two or three hours in the temperature danger zone during its entire transportation

plus it tells you the highest temperature it got to these are awesome they're kind of expensive but

some of the best vendors provide these on all of their food sure every kind of thermometer that you

might use in your restaurant you've got to know how to use a general rule of thumb

follow the manufacturer's directions but one thing that we know that we have to do

manufacturers are going to tell us but we know we have to do is we have to wash and rinse and

sanitize our probe thermometers before we stick them back into food they have to be washed rinsed

sanitized and air dried regularly and you have to make sure that the storage case of the thermometer is clean as well

you don't want to just clean the thermometer and then stick it back into the little sleeve

that's full of raw chicken that didn't do you any good be sure the sanitizing solution you use

for your probe thermometers is food grade right obviously in the picture they're using probe wipes

this is the sort of the industry standard surfsafe doesn't really talk about them

much but they are the industry standard so don't be surprised if you see a question

about a probe wipe a probe wipe is a only used to sanitize the probe it's not used to

clean it over a period of time thermometers lose their accuracy

when this happens the thermometer has got to be calibrated or adjusted to give it a correct reading you've got

to make sure your thermometers are accurate by calibrating them regularly keep in mind these three

things please some thermometers can't be calibrated and you got to throw them in the trash they're trash they

don't work anymore others especially the digital ones are going to have to be sent back to the

manufacturer for calibration and whenever you're calibrating your thermometer you're

changing what it reads when it is measuring a food temperature you better follow the manufacturer's

directions please so we're going to calibrate thermometers at some specific times

if they've been bumped or dropped if they've been exposed to an extreme temperature before deliveries before

every shift certainly and there's a couple different ways that we can go about calibrating

which is again just adjusting a thermometer so that it reads correctly we can adjust

it using the ice point method which is to adjust it based at the temperature at

which water freezes and the other is the boiling point method which is to adjust it based on

the temperature at which water boils seems pretty self-explanatory if you're going to use the boiling point

method which by the way is not nearly as popular as the ice point method because your hands have to hover above boiling

water what you're going to do is you're going to take this you're going to boil water

first of course then you're going to take your thermometer you're going to put it into

the um boiling water so much so that the dimple is under water however the tip is not

touching the metal the it's very important that the thermometer never touch

the pot that is only touching water and then what you're going to do is you're going to adjust the reading

by turning the calibration nut so that it is reading the temperature at which bottle boils which is 212 degrees

how you complete step three this last part of adjusting the thermometer is going to depend on your own

individual thermometer some of them you're going to have to read the instructions from the manufacturer

sorry reading much more common ice point method for this you're going to fill a big old

cup full of ice you're going to fill it with some water then you're going to stir it well add

your probe thermometer once again you want to insert it all the way into the water so that the dimple is

submerged the entire sensing area has got to be in the water once again you want to make sure it

doesn't touch the glass and you're going to hold it there steady for about 30 seconds until the indicator

stops moving just like we did with the boiling point method and then we're going to adjust it but

this time we're not adjusting it to the point at which water boils we're adjusting it to the point at which

water freezes which is 32 degrees so pretty straightforward right when you're using thermometers uh you

got to make sure they're accurate obviously you got to make sure they work that they're calibrated

your thermometers have to be accurate to within plus or minus 2 degrees if you're measuring food that's an

important number plus or minus 2 degrees for food plus or minus 3 degrees for air if you're measuring air

temperature is only plus or minus three glass thermometers are frequently used with candy making

and you'll never find those in a commercial restaurant unless the glass is shatterproof

because wow that would be a terrible physical contaminant wouldn't it whenever you're checking temperatures

you want to insert the thermometer into the thickest part of the food because we want to

find out if it's all the way cooked so obviously we're going to find the thickest part the part that might

still be raw potentially and then we're going to take a second reading somewhere else

so that we have an idea that the entire piece is cooked all the way remember that with the bimetallic stem

thermometer getting a good reading may take up to 30 seconds

digital thermometers the thermostars and the thermocouples two seconds two seconds three seconds

and you'll have a reading and it's a digital reading so you don't have to wait for it to like

steady on the indicator dial but by metallic stem thermometers are still quite accurate and they're very

inexpensive so there you go you're a thermometer master

congratulations [Music] so

[Music] you