Know

TCS Food

All food can potentially carry harmful bacteria, but some foods are especially conducive to promoting bacterial growth. Several factors affect the rate at which bacteria grow in food, but time and temperature are two of the most easily-controlled factors in a food service kitchen. Food that requires time and temperature control for safety is referred to as TCS food. TCS food has several attributes that make it ideal for bacterial growth, such as moisture, protein, and a neutral or slightly acidic pH.

TCS food can be whole food, or it can be food that has already been prepared, like a casserole. TCS food can be from animal or plant sources. Foods that are considered TCS include:

• Milk and other dairy products
• Meat (beef, pork, lamb) or poultry (chicken, turkey)
• Fish and shellfish
• Eggs
• Baked potatoes
• Plant-based foods that have been heat-treated (cooked rice, beans, or vegetables)
• Soy foods (tofu, textured soy protein/meat alternatives)
• Sliced or cut fruits or vegetables (e.g. cantaloupe or melons, leafy greens, tomatoes, etc.)
• Bean sprouts and sprout seeds
• Untreated garlic-and-oil mixtures

Print out the mini-poster below illustrating TCS foods and hang it in your kitchen facility, if space permits, or store the information in a Resource Binder or similiar place within your facility.

• StateFoodSafety.com's Time/Temperature Control for Safety (TCS) Foods poster

Factors That Affect Bacterial Growth

There are six factors that affect bacterial growth on food. These are food, acidity, time, temperature, oxygen, and moisture. How acidic a food is, as measured by pH, can also influence how quickly bacteria can grow. Bacteria tend to grow in foods with a pH between 4.6 and 9.0. Low pH foods—those that are more acidic—include things like pickled foods, jams or jellies, honey, and fruits. High pH foods—those that do not have much acidity—include meats, milk, and vegetables. Most bacteria that cause foodborne illness grow well in conditions that do not have much oxygen, which is why it is important to control other factors that promote bacterial growth in food. Bacteria need moisture to grow, and the amount of moisture in a food is measured by water activity. The higher the moisture in a food, the better the conditions for bacterial growth. The water activity scale ranges from 0 to 1.0, with distilled water being 1.0. Most foods have a water activity of at least 0.95, meaning that bacteria have sufficient moisture to grow.

A food handler cannot control a food’s acidity, oxygen, or moisture; these properties are inherent to the food itself. However, in food service, the remaining two factors, time and temperature, can be controlled. Time and temperature are closely related. Bacterial growth in ideal conditions happen rapidly: the amount of bacteria can double every 15 to 20 minutes. This is especially true when the temperature of food falls in the temperature danger zone. The temperature danger zone ranges from 41 F to 135 F (5 C to 74 C). The longer a food stays in this temperature range, the higher the risk for bacteria to grow rapidly in a TCS food. It is recommended to limit the length of time a TCS food is in the temperature danger zone to no more than four hours.

Controlling Time & Temperature From Receiving Through Preparation

Receiving Food

It is important to make sure you check the temperature of TCS food during the receiving process. This will help you gauge whether food was exposed to the temperature danger zone during transit. Document each food’s temperature on a designated temperature log. Refrigerated TCS foods should arrive at 41 F (5 C) or colder. Frozen TCS food should arrive at 0 F (-18 C) or colder. Hot TCS food should be received at 135 F (57 C) or higher; as with cold or frozen TCS food, be sure to document the temperature of hot TCS food upon receipt using a designated temperature log. Frozen TCS food with ice crystals or frozen liquid, fluids, or water stains should not be accepted. Additionally, any food that has passed its use-by or expiration date, has an off odor, abnormal color, or mold, or any meat, fish or poultry that is slimy, sticky, or dry should be rejected.

Storing Food

Maintaining proper temperature during storage of TCS food is very important. Temperatures should be checked and recorded regularly. Food storage time should be documented. This is accomplished through writing down the date a food was put into storage and when it should be used directly on the food itself. Labels are a good way to do this. Here are some safety tips for safely storing TCS food:

• Refrigerated TCS food should be stored at 41 F (5 C) or colder so that the internal temperature of the food maintains this temperature.
• Keep frozen food frozen; do not allow it to thaw.
• Do not overcrowd freezers or refrigerators; this can cause the temperature inside the equipment to become warmer and expose the food to dangerous temperatures.
• Minimize how often you have to open refrigerator and freezer doors.
• Label TCS food when it goes into storage. The label should include the name of the food, the date it went into storage, and the date it should be used by. Ready-to-eat TCS food prepared on-site in your facility must be used within seven days if held at 41 F (5 C) or lower.
• Be sure to rotate food during storage so that the food with the earliest use-by date is in front of foods with later dates. (As discussed in Lesson Four, this is called FIFO rotation, or first in, first out.)

The proper temperatures for kitchen equipment are as follows:

• Refrigerators: 40 F (4 C) or colder
• Freezers: 0 F (-18 C) or colder
• Dry storage: 50 F to 70 F (10 C to 21 C), with relative humidity of 50 to 60 percent

Record the temperature of your facility’s walk-in refrigerators and freezers on an approved temperature log. Your program may use a specific form, or you can use the temperature log template below.

• Walk-In Cooler Temperature Log

Thawing Food

The Academy of Nutrition and Dietetics, National Restaurant Association describes four ways to properly thaw frozen food. Which method you use depends on the type of food you thaw. It is important to thaw food properly to minimize how much time the food is in the temperature danger zone to inhibit bacterial growth.