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Apply Your Knowledge: Test Your Food Safety Knowledge
1. True or False: Chicken held at an internal temperature of
125°F (52°C) has been temperature abused
2. True or False: Infrared thermometers are best for measuring the internal temperature of food
3. True or False: When checking the temperature of a roast using a bimetallic stemmed thermometer, only the tip of the thermometer stem should be inserted into the product
4. True or False: A thermometer calibrated by the boiling-point method must be set to 135°F (57°C), after being placed into the boiling water
5. True or False: Washing and rinsing a cutting board will prevent it from cross-contaminating the next product placed on it
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Preventing Cross-Contamination
Create physical barriers between food products:
Assign specific equipment to each type of food
Clean and sanitize work surfaces, equipment, and utensils after each task
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Preventing Cross-Contamination
Create procedural barriers between food products:
Prepare raw meat, fish, and poultry and ready-to-eat food at different times (when using the same prep table)
Purchase ingredients that require minimal preparation
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Preventing Time-Temperature Abuse
This includes:
Minimizing the time food spends in the temperature danger zone
Determining the best way to monitor time and temperature
Making thermometers available
Regularly recording temperatures and the times they are taken
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The TemperatureDanger Zone
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Temperature-Measuring Devices
Bimetallic Stemmed Thermometer
Indicator Head
Calibration Nut
Holding Clip
Stem
Sensing Area
Dimple
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Temperature-Measuring Devices
Photos courtesy of Cooper-Atkins Corporation
Immersion Probe Surface Probe Penetration Probe
Thermocouples and Thermistors
Measure temperature through a metal probe or sensing area
Display results on a digital readout
Often come with interchangeable probes
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Temperature-Measuring Devices
Infrared Thermometers
Used to measure the surface temperature of food and equipment
Must be held as close to the product as possible
Remove barriers between thermometer and product
Follow manufacturers’ guidelines
Photos courtesy of Cooper-Atkins Corporation
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Apply Your Knowledge: Pick the Right Thermometer
Which temperature-measuring device should be used to check the following?
C. Bimetallic stemmed thermometer
B. ThermocoupleA. Infrared thermometer
1. Internal temperature of a hamburger patty
2. Surface temperature of a steak
3. Internal temperature of a roast
4. Internal temperature of a large stockpot of soup
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Calibrating Thermometers
Calibration
Adjusting a thermometer in order to get an accurate reading
Two methods
Boiling-point method
Ice-point method
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Calibrating Thermometers
Boiling-Point Method
1. Bring clean tap water to a boil
2. Submerge the sensing area of the thermometer stem or probe in the water for thirty seconds
3. Hold the calibration nut and rotate the thermometer head until it reads 212°F (100°C)
Note: The boiling point of water varies depending upon your elevation
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3
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Calibrating Thermometers
Ice-Point Method
1. Fill a large container with crushed ice and water
2. Submerge the thermometer stem or probe in the water for thirty seconds
3. Hold the calibration
nut and rotate the thermometer head until it reads 32˚F (0˚C)
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General Thermometer Guidelines
When using thermometers:
Keep thermometers and their storage cases clean
Calibrate them regularly to ensure accuracy
Never use glass thermometers to monitor food temperature
Insert the thermometer stem or probe into thickest part of product (usually the center)
Wait for the thermometer reading to steady before recording the temperature of a food item
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Apply Your Knowledge: Calibrate the Thermometer
Put the steps for calibrating a thermometer in the proper order:
A. Rotate the head of the thermometer until it reads 32F (0C)
B. Submerge the sensing area of the thermometer stem or probe, and wait for the reading to steady
C. Fill a container with crushed ice and clean tap water
D. Hold the adjusting nut with a wrench or other tool
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B
C
D