2. 5. The Flow of Food: An Introduction
AtTheInstitute.com
3. The Flow of Food
The path food takes through your operation. This
may include:
• Purchasing
• Receiving
• Storing
• Thawing
• Preparation
• Cooking
• Holding
• Cooling
• Reheating
• Serving
4. Section Goals
• Be able to list the • List the types of
strategies for thermometers (and
preventing cross probe attachments)
contamination. available to aid in
• Be able to list the preventing time and
strategies that aid in temperature abuse.
preventing time and • List the steps for
temperature abuse. thermometer
calibration and general
thermometer care.
5. Definitions
• Flow of Food – The path food takes through your
operation from purchasing all the way through to service.
• Thermocouple / Thermistor – An electronic (digital)
thermometer. Thermocouples are generally faster and
more accurate than bimetallic stemmed thermometers,
though more costly.
• Bimetallic Stemmed Thermometer – An common,
inexpensive foodservice thermometer.
• Calibrate – (Thermometer) To adjust a thermometer to
make it more accurate.
• Monitor – In food service operations – To measure time
& temperature to ensure safety.
6. Cross-Contamination
• Pathogens can move around easily in your
operation. They can spread from unwashed
hands or food to equipment, utensils, prep
areas and foods.
• Cross-contamination can happen at almost
any point in the flow of food.
• The most basic way to prevent cross-
contamination is to keep raw and ready-to-eat
foods away from each other.
7. How to Keep Raw & Ready-To-Eat
Foods Away From Each Other
Use Separate Equipment
• Use one set of equipment for one type of
food. For instance: yellow “poultry-only”
cutting boards, red “meat-only” cutting
boards. Blue boards for seafood and green for
produce. This gives employees a simple color
coded system to follow to keep foods
separate.
8. How to Keep Raw & Ready-To-Eat
Foods Away From Each Other
Clean & Sanitize
• Clean and sanitize all work surfaces,
equipment and utensils between tasks. Use
correct (properly mixed) sanitizers and make
sure to: Wash …then Rinse …then Sanitize.
9. How to Keep Raw & Ready-To-Eat
Foods Away From Each Other
Prep Foods At Different Times
• If you need to use the same equipment,
utensils and area to prep different types of
food that might cross-contaminate, prep them
at different times. For instance you might
prepare salad greens at a table, (then wash,
rinse, and sanitize) and then cut (or fabricate)
raw poultry afterwards.
10. How to Keep Raw & Ready-To-Eat
Foods Away From Each Other
Buying Prepared (Convenience) Foods
• Buy food items that require little or no
preparation. Pre-fabricated (pre-cut) and
cryovac-packaged steaks or washed and
chopped scallions are examples.
11. Time-Temperature Abuse
• Many foodborne illnesses happen because food has
been time & temperature abused. That is, when it’s
been allowed to remain at temperatures of 41° - 135°
F. This is called “The Temperature Danger Zone”
because pathogens grow in this range. But they grow
even faster at temperatures of 70° - 125° F. You may
wish to think of this as a “super-danger” zone.
• Food is being Time & Temperature Abused when:
• Cooked to the wrong (too low) temperature
• Held at the wrong temperature
• Cooled or reheated incorrectly
12. Avoiding Time & Temperature Abuse
Monitoring
• Learn which food items should have their
temperature checked, how often and by
whom. Then assign duties to foodhandlers in
each area.
13. Avoiding Time & Temperature Abuse
Tools
• Ensure that employees have the right
thermometers available and the training to
use them effectively. Use times in prep areas
to check how long food is in The Temperature
Danger Zone.
14. Avoiding Time & Temperature Abuse
Recording
• Have foodhandlers record temperatures as a
normal part of their duties. Make sure
temperatures are being written down at the
time they are taken.
15. Avoiding Time & Temperature Abuse
Time & Temperature Control Procedures
• Have procedures that limit the time food
spends in The Temperature Danger Zone. This
might include a policy for removing only a
small amount of a product from refrigeration
at one time or standardized recipes with built-
in control procedures.
16. Avoiding Time & Temperature Abuse
Corrective Actions
• Make sure foodhandlers know what to do
when temperature standards are not met. For
instance, when soup, being held on a steam
table falls below 135°F. after two hours, it
needs to be reheated to the correct
temperature.
17. Monitoring Time & Temperature
To keep food safe you must limit the time it spends
in The Temperature Danger Zone. The two most
important tools used for this are clocks/timers
and thermometers. There are three common
types of thermometers we use in foodservice:
• Bimetallic Stemmed Thermometers
• Thermocouples
• Thermistors
NOTE: For our purposes Thermocouples and Thermistors are interchangeable
so that in fact we will choose either Bimetallic Stemmed Thermometers OR
Thermocouples/Thermistors.
18. Bimetallic Stemmed Thermometers
Bimetallic Stemmed Thermometers can
check temperatures from 0° - 220° F.
When buying this type of thermometer
for your operation, follow these
guidelines:
• Make sure there is a Calibration Nut or Method
of Calibration to ensure accuracy
• It should have Easy to Read Markings
• Make sure there is a dimple on the stem that
marks the end of the sensing area.
• The thermometer must be guaranteed accurate
to within ±2 degrees F.
19. Thermocouples & Thermistors
Thermocouples & thermistors
check temperatures
electronically using various
attachment probes and display
the temperature digitally. They
are useful for thin or thick
foods because the sensing area
is only at the tip of the probe.
20. Thermocouple Probes
Immersion Probes
• Use these to check the
temperature of liquids like
soups, sauces and fryer
oil..
21. Thermocouple Probes
Surface Probes
• Use these to check the
temperature of cooking
equipment such as
griddle tops.
22. Thermocouple Probes
Penetration Probes
• Use these to check the
internal temperature of
foods. This type of probe
is especially useful for
thin foods like fish fillets
and burgers.
23. Thermocouple Probes
Air Probes
• Use these to check the
temperature inside
coolers and ovens.
24. Infrared (Laser) Thermometers
Infrared Thermometers measure the
surface temperature of items.
Because there is no contact between
the thermometer and the food or
item, this type of thermometer
minimizes cross-contamination risks.
Follow these guidelines:
• Hold the thermometer close to the food or
item being measured
• Remove any barriers between the food/item
and the thermometer such as packaging
• Always follow the manufacturer’s instructions
for use.
25. Time-Temperature Indicators (TTI)
Time-Temperature Indicator (TTI)
tags are sometimes placed
inside delivery vehicles and on
food packaging. A color change
on the tag can tell you if the
food has been time &
temperature abused.
26. Calibrating Thermometers
Thermometers can lose their accuracy when
bumped or dropped or when they go through
extreme temperature changes. When this
happens, thermometers need to be calibrated
(adjusted) so that they remain accurate.
• Thermometers may be calibrated by either of
these methods:
• Ice-Point Method (32° F.)
• Boiling-Point Method (212° F.)
27. Ice-Point Method for Calibrating
Thermometers
• Fill a large container with crushed ice. Add cold
tap water until the container is full.
Stir the mixture well.
• Put the thermometer stem (sensing area) into
the ice-water. Wait at least 30 seconds or until
the indicator/readout stops moving.
Do not let the probe touch the sides of the container.
• Adjust the thermometer so that it reads 32° F.
This is done by turning a calibration nut or following the
manufacturer’s instructions for calibration.
28. Boiling-Point Method for Calibrating
Thermometers
• Bring tap water to a boil in a deep pot/pan.
• Put the thermometer stem (sensing area) into
the boiling water. Wait at least 30 seconds or
until the indicator/readout stops moving.
Do not let the probe touch the sides of the pot/pan.
• Adjust the thermometer so that it reads 212° F.
This is done by turning a calibration nut or following the
manufacturer’s instructions for calibration.
NOTE: Boiling-point temperature may vary depending upon your
elevation relative to sea-level. Adjust accordingly.
29. Additional Thermometer Guidelines
Employees must be properly trained on how to use and care for the
types of thermometers they will be using. This includes:
• Cleaning & Sanitizing – Thermometers must be washed, rinsed, sanitized, and
air-dried to be safe for food contact.
• Calibration – Thermometers should be calibrated at the start of each shift,
prior to the day’s first delivery, when dropped or bumped, or when they go
through extreme temperature changes.
• Accuracy – Some thermometers cannot be calibrated. (Oven & Cooler
thermometers) These thermometers should be checked by comparing
temperatures to a calibrated thermocouple and replaced if needed.
• Glass Thermometers – Never use glass thermometers to check food
temperatures..
• Checking Temperatures – When checking temperatures insert the probe into
the thickest part of the food. (Also take another reading in a different spot as
these temperatures may differ.) It can take 15 – 30 seconds to get an accurate
reading depending upon the type and quality of thermometer used.
31. JNA Institute of Culinary Arts
215.468.8800
http://culinaryarts.edu
Notas do Editor
Hello and welcome to AtTheInstitute.com’s online preparatory course for the National Restaurant AssociationServSafe Manager Certification Exam.
This will be chapter or section five of the course: The Flow of Food: An Introduction
Before we begin we should talk about what “flow of food” means. The flow of food is the path food takes through the operation. It is everything that happens to that food.And may include some or all of these steps:PurchasingReceivingStoringThawingPreparationCookingHoldingCoolingReheatingAnd Serving
Our goals for this section will be:Be able to list the strategies for preventing cross contamination.Be able to list the strategies that aid in preventing time and temperature abuse.List the types of thermometers (and probe attachments) available to aid in preventing time and temperature abuse.List the methods and steps for thermometer calibration and general thermometer care.
As always, more definitions to help you understand this section. We have the afore-mentioned Flow of Food – That is the path food takes through your operation from purchasing all the way through to service.Thermocouple or Thermistor – Thermocouples and thermistors are electronic (digital) thermometers. They’re are generally faster and more accurate than standard,bimetallic, stemmed thermometers, though more costly.Bimetallic Stemmed Thermometer – Are common, inexpensive foodservice thermometers.To calibrate – (speaking of thermometers) means to adjust a thermometer to make it more accurate.And monitor – In this context, monitor means to measure time & temperature to ensure safety.
Cross-contamination can happen at almost any point in the flow of food. When you know how and when it happens, it is fairly easy to prevent. The most basic way is to keep raw and ready-to-eat foods separate for one another. Remember, pathogens can move around easily in your operation. They can spread from unwashed hands (or food) to equipment, utensils, prep areas and other foods.
To Keep Raw & Ready-To-Eat Foods Away From Each Other:Use Separate Equipment - Use one set of equipment for one type of food. For instance: yellow “poultry-only” cutting boards, red “meat-only” cutting boards. Blue boards for seafood and green for produce. This gives employees a simple color coded system to follow to keep foods separate.
A second option is to clean & sanitize. Clean and sanitize all work surfaces, equipment and utensils between tasks. Use correct (properly mixed) sanitizers and make sure to: Wash …then Rinse …then Sanitize.
A third option is to Prep Foods At Different TimesIf you need to use the same equipment, utensils and area to prep different types of food that might cross-contaminate, prep them at different times. For instance you might prepare salad greens at a table, (then wash, rinse, and sanitize) and then cut (or fabricate) raw poultry afterwards.
Lastly, where the first three methods are not practical you can buy prepared foods – that is food items that require little or no preparation. Pre-fabricated (pre-cut) and cryovac-packaged steaks, pre-cut and grilled, frozen chicken breasts or washed and chopped scallions are examples.
Many foodborne illnesses happen because food has been time & temperature abused. That is, when TCS food has been allowed to remain at temperatures of 41° - 135° F. This is called “The Temperature Danger Zone” because pathogens grow in this range. But pathogens grow even faster at temperatures between 70° and 125° F. You may wish to think of this as a sort of “super-danger” zone. Remember:Food is being Time & Temperature Abused when it is:Cooked to the wrong (too low) temperatureHeld at the wrong temperatureOr cooled or reheated incorrectly
To help combat Time-Temperature abuse:MonitorLearn which food items should have their temperature checked, how often and by whom. Then assign those duties to foodhandlers as necessary.
The next way to combat Time-Temperature abuse is:Having the right tools:Ensure that employees have the right thermometers available and the training to use them effectively. Use timers or clocks in prep areas to check how long food is in The Temperature Danger Zone.
Our third way to combat Time-Temperature abuse is:RecordingHave foodhandlers record temperatures as a normal part of their duties. Make sure temperatures are being written down at the time they are taken
The fourth way to combat Time-Temperature abuse is:Provide Time & Temperature Control ProceduresHave procedures that limit the time food spends in The Temperature Danger Zone. This might include a policy for removing only a small amount of a product from refrigeration at one time or standardized recipes with built-in control procedures.
And lastly, have:Corrective ActionsMake sure foodhandlers know what to do when temperature standards are not met. For instance, when soup, being held on a steam table falls below 135°F. after two hours, it needs to be reheated to the correct temperature.
To keep food safe you must limit the time it spends in The Temperature Danger Zone. The two most important tools used for this are clocks/timers and thermometers. There are three common types of thermometers we use in foodservice: Bimetallic Stemmed ThermometersThermocouplesThermistorsNOTE: For our purposes Thermocouples and Thermistors are interchangeable so that in fact we will choose either Bimetallic Stemmed Thermometers OR Thermocouples/Thermistors or some combination of the three.
Bimetallic Stemmed Thermometers can check temperatures from 0° - 220° F. When buying this type of thermometer for your operation, follow these guidelines: Make sure there is a Calibration Nut or Method of Calibration to ensure accuracyIt should have Easy to Read MarkingsMake sure there is a dimple on the stem that marks the end of the sensing area.And ensure that the thermometer isguaranteed accurate to within ±2 degrees Fahrenheit.
Thermocouples & thermistors check temperatures electronically using various attachment probes and display the temperature digitally. They are useful for thin or thick foods because the sensing area is only at the tip of the probe.
Types of probes include:Immersion ProbesUse these to check the temperature of liquids like soups, sauces and fryer oil..
Surface ProbesUse these to check the temperature of cooking equipment such as griddle tops.
Penetration ProbesUse these to check the internal temperature of foods. This type of probe is especially useful for thin foods like fish fillets and burgers.
And Air ProbesUse these to check the temperature inside coolers and ovens.
Another kind of thermometer is theInfrared ThermometerInfrared Thermometers measure the surface temperature of items. Because there is no contact between the thermometer and the food or item, this type of thermometer minimizes cross-contamination risks. Follow these guidelines:Hold the thermometer close to the food or item being measuredRemove any barriers between the food/item and the thermometer such as packagingAnd Always follow the manufacturer’s instructions for use.
You may also see TTI’sTime-Temperature Indicator (TTI) tags are sometimes placed inside delivery vehicles and on food packaging. A color change on the tag can tell you if the food has been time & temperature abused.
Thermometers can lose their accuracy when bumped or dropped or when they go through extreme temperature changes. When this happens, thermometers need to be calibrated (that is, adjusted) so that they remain accurate. Thermometers may be calibrated by either the:Ice-Point Method (32° F.) orThe Boiling-Point Method (212° F.)
To calibrate a thermometer using the ice-point method:Fill a large container with crushed ice. Add cold tap water until the container is full. Stir the mixture well.Put the thermometer stem (sensing area) into the ice-water. Wait at least 30 seconds or until the indicator/readout stops moving.Do not let the probe touch the sides of the container.Adjust the thermometer so that it reads 32° F.This is done by turning a calibration nut or following the manufacturer’s instructions for calibration.
To calibrate a thermometer using the boiling-point method:Bring tap water to a boil in a deep pot/pan. Put the thermometer stem (sensing area) into the boiling water. Wait at least 30 seconds or until the indicator/readout stops moving.Do not let the probe touch the sides of the pot/pan.Adjust the thermometer so that it reads 212° F.This is done by turning a calibration nut or following the manufacturer’s instructions for calibration.NOTE: The Boiling-point temperature may vary depending upon your elevation relative to sea-level. Adjust accordingly.
Employees must be properly trained on how to use and care for the types of thermometers they will be using. This includes: Proper Cleaning & Sanitizing – Thermometers must be washed, rinsed, sanitized, and air-dried to be safe for food contact.Calibration – Thermometers should be calibrated at the start of each shift, prior to the day’s first delivery, when dropped or bumped, or when they go through extreme temperature changes.Accuracy – Some thermometers cannot be calibrated. (Oven & Cooler thermometers) These thermometers should be checked by comparing temperatures to a calibrated thermocouple and replaced if needed.Glass Thermometers – Never use glass thermometers to check food temperatures..Checking Temperatures – When checking temperatures insert the probe into the thickest part of the food. (Also take another reading in a different spot as these temperatures may differ.) It can take 15 – 30 seconds to get an accurate reading depending upon the type and quality of thermometer used.
All of the information provided can be found in The National Restaurant Association’s, ServSafe Essentials, 5th Edition with 2009 FDA Food Code Updates.For more information go to their site. www.servsafe.com.
Your next step is to tackle the review questions for this section before continuing on to section Six of the course.For AtTheInstitute.com, this is [your name]. Leave us any feedback you might have regarding this course by email at feedback@AtTheInstitute.com.Thank You.