Record-breaking heat across much of the country this summer is placing enormous challenges on food safety as products are transported over a long hot journey from farm to fork.

In today’s global food industry, foods often travel thousands of miles from where they were produced. Temperature-sensitive foods are distributed by air, sea, rail, and road across countries, continents, and oceans – all affected by extreme and unpredictable changes in the weather. 

Across the distribution network known as the cold chain, these foods require precise temperature controls for quality and safety. The cold chain refers to the temperature-controlled supply chain comprising a series of links stretching around the world.

Refrigerated packing houses, food processors, and retail locations are all part of this cold chain linked by the distribution industry, which is tasked with maintaining temperature controls that ensure the quality and safety of produce and foods that are refrigerated and frozen.   

Temperature fluctuations during storage and transport can cause food quality and safety issues, resulting in shortened shelf life, spoiled shipments, and foodborne illnesses. Excessive heat can make maintaining proper temperatures during transportation harder, causing refrigeration trucks to falter and shipping docks to overheat.

A single broken link in this delicate cold chain can result in contaminated foods. To appreciate the fragility of this network, a high-quality food safety training program can help employees understand and spot food quality and safety hazards in transit. Here’s a look at what they can learn.

Climate effects on foods
Foods stored or shipped outside their optimal temperature range can undergo physical damage that makes them unfit for sale. Produce can freeze or wilt, oils can separate, and ice cream can crystalize.

Higher temperatures can increase the growth rate of molds, yeasts, and enzymes, which can cause food to spoil more quickly. These are all critical food quality issues employees should understand. But keeping food at the correct temperature is about more than quality.

Exposing food to unsafe temperatures for prolonged periods promotes the growth of dangerous bacteria or pathogens, which presents a food safety hazard. Potential sources of pathogens can come from multiple points across the manufacturing and supply chains.

Fortunately, most pathogens can be killed or reduced to safe levels with heat treatment by cooking or pasteurizing the food. But some ready-to-eat foods can be re-contaminated with dangerous bacteria before they are packaged.

Food safety danger zones
Although many different types of bacteria exist, they need four conditions to grow: food, moisture, temperature, and time. Bacteria grow fastest in a temperature range known as the Temperature Danger Zone (TDZ), between 41- and 135 degrees Fahrenheit, (5- to 57 Celsius.) Foods stored at 70 degrees Fahrenheit (21 Celsius) for four hours experience the most bacteria growth and can be dangerous to eat.

Foods at most risk in the TDZ are called Time and Temperature Control for Safety foods, or TCS foods. When TCS foods are exposed to the TDZ, they become “temperature abused.”  

Transportation
During transportation, the cold chain is at its greatest risk. Refrigerated trailers, or reefers, are designed to maintain temperatures, not cool food down. If the trailer or the load is not pre-cooled to the correct temperature before loading, the reefer’s cooling system could be overwhelmed.

For most other frozen foods, 0 degrees Fahrenheit  (-17.7 Celsius)  is the normal cooling temperature, with 10- to 20 degrees Fahrenheit (-12.2 to -6.6 Celsius) set as a receiving limit. Fresh foods, super-chilled meat, and seafood must be kept just under freezing, between 29-32 degrees Fahrenheit (-1.6 to 0 Celsius).  

Fresh foods such as produce, dairy, meat, and seafood should be stored between 33- and 40-degrees Fahrenheit (0.5 – 4.4 Celsius). Typical refrigerated truck temperatures for fresh foods might range between 38- and 40 degrees. At 41 degrees Fahrenheit (5 Celsius), the Temperature Danger Zone begins for TCS foods.

Problems can occur when  refrigeration (reefer) units struggle to keep up with outside temperatures. If airflow is blocked by improperly placed pallets inside a trailer, the reefer unit can short cycle, potentially compromising the load. Foods are also put at risk when loaded and unloaded at unrefrigerated docks.

Once on the road, reefer temperatures must be monitored to ensure that temperature is being maintained. Otherwise, an unscrupulous driver could set the reefer a little high to save fuel on a long-haul route. And the reefer unit must function properly during its entire journey to maintain safe temperatures.

Training for employee support
Training is available to help employees understand their role in keeping food safe during its long journey through the global cold chain. For example, employees at a distribution facility can learn how to verify if the temperature of TCS food arriving or leaving is within a facility’s temperature standards.

Training can help drivers ensure their reefer units maintain the correct temperature range while on the road, which may include recording the temperature when they open a trailer at the delivery stop. Throughout all jobs, employees should be able to verify the products they handle are at the correct temperature.

They can learn how to use a regularly calibrated thermometer, follow their company’s temperature sampling procedures, and properly document the results. More importantly, they can help maintain the cold chain by following their company’s temperature monitoring procedures.

Training can also help employees at a processing facility or refrigerated warehouse know what to look for when a load is received or shipped that could signify temperature abuse.

It can take hundreds of trained and motivated employees to maintain the cold chain across thousands of miles. Even during the hottest days and most extended periods of heat, employees can be the best frontline defense to protect fragile products from the food safety danger zone.   

Contact us to learn more about food safety training and how to keep foods safe throughout the entire cold chain.