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The Flow of Food: An Introduction. Apply Your Knowledge: Test Your Food Safety Knowledge. True or False: Chicken held at an internal temperature of 125 ° F (52 ° C) has been temperature abused True or False: Infrared thermometers are best for measuring the internal temperature of food
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Apply Your Knowledge: Test Your Food Safety Knowledge • True or False: Chicken held at an internal temperature of 125°F (52°C) has been temperature abused • True or False: Infrared thermometers are best for measuring the internal temperature of food • 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 • 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 • True or False:Washing and rinsing a cutting board will prevent it from cross-contaminating the next product placed on it 5-2
The Flow of Food • To keep food safe: • Prevent cross-contamination • Prevent time-temperature abuse
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
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
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 The TemperatureDanger Zone Microorganisms grow rapidly Microorganisms survive and grow
Temperature-Measuring Devices • Bimetallic Stemmed Thermometer Indicator Head Calibration Nut Holding Clip Stem Sensing Area Dimple
Temperature-Measuring Devices • Thermocouples and Thermistors • Measure temperature through a metal probe or sensing area • Display results on a digital readout • Often come with interchangeable probes Immersion Probe Surface Probe Penetration Probe Photos courtesy of Cooper-Atkins Corporation
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
Internal temperature of a hamburger patty Surface temperature of a steak Internal temperature of a roast Internal temperature of a large stockpot of soup 1 2 3 4 B. Thermocouple C. Bimetallic stemmed thermometer Apply Your Knowledge: Pick the Right Thermometer • Which temperature-measuring device should be used to check the following? A. Infrared thermometer 5-10
Calibrating Thermometers • Calibration • Adjusting a thermometer in order to get an accurate reading • Two methods • Boiling-point method • Ice-point method
Calibrating Thermometers • Boiling-Point Method • Bring clean tap water to a boil • Submerge the sensing area of the thermometer stem or probe in the water for thirty seconds • 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 1 2 3
Calibrating Thermometers Ice-Point Method 1. Fill a largecontainer 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)
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
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 A B C D 5-15