From “Perishable Foods” to Time/Temperature Control for Safety (TCS) – Part 1


When people think of “perishable foods” they often think of milk or meat, but in actuality the types of foods that fall into this category are much broader. The term perishable is used to emphasize that the shelf life of these foods is limited or likely to go rancid quickly, if not refrigerated. This term has evolved quite a bit over the years. The most recent name, within the industry, is Time/Temperature Control for Safety or TCS.

In Part 1, we will explore the meaning of TCS, what foods fall under its umbrella, and what a business needs to consider when it comes to food safety and the proper handling or management of these items.

The Switch to TCS

Although the term “perishable foods” is still used in regular conversation to reference food that needs to be refrigerated, the definition of the phrase has changed over the years in related industry circles. The general thought behind the shift in how we reference these foods responds to the fact that foodborne illnesses are a serious consideration for everyone involved in the supply chain.

The first shift was from perishable foods to “potentially hazardous foods” or PHF to better highlight the threats presented by food that was not correctly transported. 

Over the last several years, the phrase that is gaining the most familiarity is Time/Temperature Control for Safety or TCS. The expression TCS recognizes that there are two ways best to prevent contamination and bacteria growth: time and temperature. Both TCS and PHF are used interchangeably, as it relates to food products, but TCS is becoming more commonly referenced within the Supply Chain industry.  

Types of TCS Foods

Foods that fall into the category of Time/Temperature Control for Safety(TCS) or perishable food include (Reference: Food Safety):

  • Milk and dairy products
  • Eggs
  • Leafy greens
  • Fish
  • Shellfish
  • Sliced melons
  • Tomatoes
  • Meat
  • Poultry
  • Protein-rich plants
  • Cream
  • Custard
  • Cooked vegetables
  • Raw sprouts and seeds
  • Cut leafy greens
  • Garlic in oil
  • Potato dishes

TCS foods are more vulnerable to bacteria and pathogen growth.

The Safety Behind TCS Foods

Bacteria need a few things to grow: time, warmth, acidity, oxygen, moisture, and nutrients. Since those involved in the supply chain do not influence the compositional elements of these foods, the two controllable factors are time and temperature.


Bacteria need surprisingly little time to grow. Too much bacteria on a food item can easily lead to a foodborne illness, which is why “time” is such an essential factor when protecting these products. Bacteria can double in amounts every 20 minutes when the temperature is not controlled correctly.


Temperature is closely related to “time” for these foods. The “Temperature Danger Zone” is 41°F to 135° F or 5° C to 57.2° C. Foods left out in the danger zone can quickly become a breeding ground for the bacteria. Within four hours of high temperatures, most food will have to be tossed as it will be a potential case of foodborne illness.

For refrigerated foods, the ideal temperature range is 32°F to 40°F or 0° to 4°C. Frozen foods should be kept at a temperature lower than 0°F or -18°C.

Time and Temperature Should Work Together for Food Safety Control

Time and temperature work best together when it comes to the care and safety of TCS foods. Cold temperatures are the best option for keeping bacteria levels low, and the longer the foods are out of that temperature range, the more likely the food will be contaminated and wasted.

Time alone is dangerous for TCS foods as it is incredibly prone to human error. Mistakes in lengths of time could result in contaminated foods being served. Temperatures must also be monitored over this entire time period to determine best if the food item is at the right temperature to be served. For example, “cold foods can be served for six hours as long as the food temperature stays below 70° Fahrenheit” in restaurants. Any cold food items over that temperature should be discarded. If the temperature isn’t regularly checked during this time period, the food will need to be thrown out as well.

The temperature within a storage space also needs to be monitored, as it does tend to fluctuate. Different types of pathogens respond differently to ranges of temperatures, so just as with time, temperatures should be overseen by everyone involved in the supply chain.

“Perishable foods” need the right environment to prevent the growth of bacteria and to help protect your end consumer. Time/Temperature Control for Safety is one of the best ways to achieve this, so everyone in the supply chain needs to be involved in keeping the food safe. 

To ensure safety and compliance throughout the supply chain consistent monitoring of temperature should be maintained, in storage and transport, from the origin of the food to the business the TCS food is being delivered and final purchase or consumption by the consumer. 

Join us for Part 2 of this series where we will cover the importance of safety throughout the entire food supply chain from Origin to Consumer Purchase.

At Magnetic Precision, we understand the importance of TCS transportation options when it comes to perishable products and is here to help your organization every step of the way. Discover more about what we do in cold chain management for these food items. Visit our website For inquiries and questions, contact us at [email protected].

Vanesia Adkins, 5/17/2020