Chapter 5 - HMGT 251

time-temperature indicator (TTI)

A color change appears in the TTI window if the food has been time-temperature abused during shipment or storage. This color change is not reversible, so you know if the item has been abused.

Step 3

Adjust the thermometer so it reads 32°F (0°C). To calibrate a bimetallic stemmed thermometer, adjust it by holding the calibration nut with a wrench or other tool. To calibrate a thermocouple or thermistor, follow the manufacturer's directions.

What should be used to check the internal temperature of thin​ food, such as meat or fish​ patties?

Penetration probe

Which is a strategy for reducing the risk of​ cross-contamination?

buying prepared food

The adjustment of this makes the thermometer accurate.

calibration nut

A food handler has finished trimming raw chicken on a cutting board and needs it to prep vegetables. This cutting board must be ____ before doing this.

washed, rinsed, and sanitized

does time play a critical role?

yes-Time also plays a critical role. The longer food stays in the temperature danger zone, the more time pathogens have to grow. To keep food safe, you must reduce the time food spends in this temperature range. TCS food must be thrown out if it stays in the temperature danger zone for four hours or more.Food handlers should avoid time-temperature abuse by following good policies and procedures.

To keep food safe, you must control the amount of time it spends in the temperature danger zone. This requires monitoring food temperatures. The most important tool you have is the thermometer. There are many types of thermometers. Three types are commonly used in foodservice operations:

-Bimetallic stemmed thermometers -Thermocouples -Thermistors

To calibrate a thermometer using the boiling-point method, follow these steps:

-Bring clean tap water to a boil in a deep pan. -Put the thermometer stem or probe into the boiling water. Make sure the sensing area is submerged. Wait 30 seconds or until the indicator stops moving. Do not let the stem or probe touch the container. -Adjust the thermometer so it reads 212°F (100°C).

If you buy bimetallic stemmed thermometers for your operation, make sure they have the following features.

-Calibration nut: You can make the thermometer accurate by adjusting its calibration nut. -Easy-to-read markings: Clear markings reduce the chance that someone will misread the thermometer. The thermometer must be scaled in at least two-degree increments. -Dimple: The dimple is the mark on the stem that shows the end of the temperature-sensing area

Follow these guidelines for using infrared thermometers.

-Distance: Hold the thermometer as close to the food or equipment as you can without touching it. -Barriers: Remove anything between the thermometer and the food, food package, or equipment. Avoid taking readings through metal, such as stainless steel or aluminum, or through glass. -Manufacturer's directions: Always follow the manufacturer's guidelines. This should give you the most accurate readings.

When checking the temperature of food:

-Insert the thermometer stem or probe into the thickest part of the food. This is usually in the center. -Take another reading in a different spot. The temperature may vary in different areas.

There are two ways to calibrate a thermometer:

-The ice-point method involves adjusting the thermometer to the temperature at which water freezes (32°F [0°C]). -The boiling-point method involves adjusting the thermometer to the temperature at which water boils (212°F [100°C], depending on your elevation).

notes on boiling-point method

-This temperature will vary depending on the boiling point for your elevation. Water's boiling point is about 1°F (about 0.5°C) lower for every 550 feet (168 meters) above sea level. -If you are using a bimetallic stemmed thermometer, adjust it by holding the calibration nut with a wrench or other tool. -If you are using a thermocouple or thermistor, some devices will let you press a reset button. Always follow the manufacturer's directions.

When using the​ ice-point method to calibrate a​ thermometer, what should the temperature reading be set​ to?

32°F (0°C)

TCS food has been​ time-temperature abused anytime it remains between

41degrees°F ​(5degrees°​C) and 135degrees°F ​(57degrees°​C).

bimetallic stemmed thermometer checks temperatures

A bimetallic stemmed thermometer checks temperatures from 0°F to 220°F (-18°C to 104°C). This makes it useful for checking temperatures during the flow of food. For example, you can use it to check food temperatures both during receiving and in a hot- or cold-holding unit.

bimetallic stemmed thermometer measures temperatures, how?

A bimetallic stemmed thermometer measures temperatures through a metal stem. When checking temperatures, insert the stem into the food up to the dimple. You must do this because the sensing area goes from the tip of the stem to the dimple. This trait makes the thermometer useful for checking the temperature of large or thick food. It is usually not practical for thin food, such as hamburger patties.

Where is a​ time-temperature indicator​ (TTI) most commonly​ found?

Attached to the packaging of a food shipment

Before recording a temperature

Before recording a temperature, wait for the thermometer reading to steady. While digital thermometers can display the temperature instantly, bimetallic stemmed thermometers need at least 15 seconds after you insert the thermometer stem into the food.

When using the​ boiling-point method for​ calibration, what is the first step of the​ process?

Bring clean tap water to a boil in a deep pan.

Buy Prepared Food

Buy food that does not require much prepping or handling. For example, you could buy precooked chicken breasts or chopped lettuce.

Clean and Sanitize Before and After Tasks

Clean and sanitize all work surfaces, equipment, and utensils after each task. When you cut up raw chicken, for example, you cannot get by with just rinsing the equipment. Pathogens such as nontyphoidal Salmonella can contaminate food through cross-contamination. To prevent this, you must wash, rinse, and sanitize equipment.

Ways of preventing cross-contamination

Cross-contamination is a major hazard in the flow of food. Pathogens can be spread from food or unwashed hands to prep tables, utensils, equipment, or other food. Cross-contamination can occur at almost any point within the flow of food. When you know how and where it can happen, it is fairly easy to prevent. The most basic way is to keep raw and ready-to-eat food away from each other.

Use Separate Equipment for Raw and Ready-to-Eat Food

Each type of food should have separate equipment. For example, use one set of cutting boards, utensils, and containers for raw poultry. Use another set for raw meat. Use a third set for produce.Colored cutting boards and utensil handles can help you keep equipment separate. The color tells food handlers which equipment to use with each food item. They might use yellow for raw chicken, red for raw meat, and green for produce.

Step 1

Fill a large container with ice. Use crushed ice if you have it.Add tap water until the container is full. Stir the mixture well.

Recording

Have food handlers record temperatures regularly, as the chef is doing in the photo at left. Make sure they write down when the temperatures were taken. Print simple forms for recording this information. Post them on clipboards outside of coolers and freezers, near prep areas, and next to cooking and holding equipment.

Time and Temperature Control

Have procedures to limit the time TCS food spends in the temperature danger zone. This might include limiting the amount of food that can be removed from a cooler when prepping the food.

Prep Raw and Ready-to-Eat Food at Different Times

If you need to use the same prep table for different types of food, prep raw meat, fish, and poultry at a different time than ready-to-eat food. You must clean and sanitize work surfaces and utensils between each type of food. Also, if you prep ready-to-eat food before raw food, you can reduce the chance for cross-contamination.

Food is being time-temperature abused whenever it is handled in the following ways:

It is cooked to the wrong minimum internal temperature It is held at the wrong temperature It is cooled or reheated incorrectly

Monitoring

Learn which food items should be checked, how often, and by whom. Make sure food handlers understand what to do, how to do it, and why it is important.

Which is a strategy for reducing the risk of​ time-temperature abuse?

Limit the amount of TCS food that can be removed from a cooler when prepping it.

Corrective Actions

Make sure food handlers know what to do when time and temperature standards are not met. For example, if you hold soup on a steam table and its temperature falls below 135°F (57°C) after two hours, you might reheat it to the correct temperature or throw it out

Tools

Make sure the correct kinds of thermometers are available. Give food handlers their own thermometers. Have them use timers in prep areas to check how long food is in the temperature danger zone.

flow of food

Many things can happen to food as it moves from purchasing and receiving through storing, prepping, cooking, holding, cooling, reheating, and serving.

Step 2

Put the thermometer stem or probe into the ice water. Make sure the sensing area is submerged. Wait 30 seconds or until the indicator stops moving. Do not let the stem or probe touch the container.

Thermocouples and Thermistors

The difference between them is the technology inside.Thermocouples and thermistors measure temperatures through a metal probe. Temperatures are displayed digitally. The sensing area on thermocouples and thermistors is on the tip of their probe. This means you do not have to insert them into the food as far as bimetallic stemmed thermometers to get a correct reading. Thermocouples and thermistors are good for checking the temperature of both thick and thin food.Thermocouples and thermistors are available in multiple sizes and styles. Many come with different types of probes.

Ice-Point Method

The ice-point method of calibration is easier and safer than the boiling-point method.

How to calibrate thermometers

Thermometers can lose their accuracy when they are bumped or dropped. It can also happen when they go through a severe temperature change. When this happens, the thermometer needs calibration, or an adjustment, to give a correct reading. Thermometers that cannot be calibrated should be replaced. Others might need to be sent back to the manufacturer for calibration. Always follow the manufacturer's directions.

Some suppliers place temperature-recording devices inside their delivery trucks

These devices constantly monitor and record temperatures. You can check the device during receiving to make sure food remained at safe temperatures while it was being shipped.

Why do glass thermometers require special care when being​ handled?

They are relatively fragile and can become a physical contaminant if they break.

maximum registering thermometer

This thermometer indicates the highest temperature reached during use. It is used where temperature readings cannot be continuously observed. It works well for checking final rinse temperatures of dishwashing machines.

Ways of preventing time-temperature abuse

Time-temperature abuse is another major hazard in the flow of food.Remember, TCS food has been time-temperature abused any time it remains between 41°F and 135°F (5°C and 57°C). This is called the temperature danger zone because pathogens grow in this range. They grow especially fast between 70°F and 125°F (21°C and 52°C).

Penetration Probes

Use these to check the internal temperature of food. They are especially useful for checking the temperatures of thin food, such as fish fillets or hamburger patties.

Air Probes

Use these to check the temperature inside coolers and ovens.

Immersion Probes

Use these to check the temperature of liquids. This could include soups, sauces, and frying oil.

Surface Probes

Use these to measure the temperature of flat cooking equipment, such as griddles.

TCS food has been ____ if it remains in the temperature danger zone for extended periods of time.

abused

Which type of probe would be used to check the temperature inside coolers and​ ovens?

air

The mark on the stem of the thermometer that shows the end of the temperature-sensing area.

dimple

Degree increments that allow people to read the thermometer.

easy-to-read temperature markings

After cutting up raw chicken, rinsing the cutting board is enough before switching to vegetables. t/f

false

When calibrating a thermometer, the method involving adjusting it based on the temperature at which water freezes is called the ____.

ice-point method

A(n) ____ probe should be used to check the temperature of a large stockpot of chili.

immersion

Infrared (Laser) Thermometers

measure the temperatures of food and equipment surfaces. These thermometers are quick and easy to use.Infrared thermometers do not need to touch a surface to check its temperature. This means there is less chance for cross-contamination and damage to food. However, these thermometers cannot measure air temperature or the internal temperature of food.

When different types of food must be prepped on the same​ table, which of these types of food should be prepped first to minimize the risk of​ cross-contamination?

ready-to-eat food

The long metal part of the thermometer just under the indicator head.

stem

Fill a large container with crushed ice. Add tap water until the container is full.

step 1

Put the thermometer stem or probe into the ice water. Make sure the sensing area is submerged. Wait 30 seconds or until the indicator stops moving.

step 2

Adjust the thermometer so it reads 32°F (0°C).

step 3

Recording ____ regularly, and posting the information on clipboards outside of coolers and freezers, near prep areas, and next to cooking and holding equipment is one way to avoid time-temperature abuse.

temperatures

The benefit of purchasing a thermistor instead of a bimetallic stemmed thermometer is ____.

the sensing area is in the tip of the stem

Procedures that limit the time TCS food spends in the temperature danger zone are part of ____.

time and temperature control

A time-temperature indicator (TTI) records the temperature using color changes. The purpose of the color when checked is ____.

to indicate that the food has been time-temperature abused during shipment

A bimetallic stemmed thermometer must be inserted ____ into food to give an accurate reading.

up to the dimple of the stem