Maintaining consistently high food quality standards is a determining factor of supermarket success, impacting both customer loyalty and bottom-line profitability. Although consumers may take for granted how their favorite produce arrived on the shelf, they’re more discerning about evaluating its quality. Shoppers check for appearance and texture in the store as the first signs of freshness, while taste is the ultimate confirmation of quality.
In the perishable cold chain, proper temperature management is the key to ensuring maximum quality, freshness and shelf life. When considering the number of steps and stakeholders involved throughout the cold chain — where production and shipping processes are prone to mistakes — the margins for error are surprisingly slim.
The ideal holding temperature will vary depending on the type of perishable commodity. For example, most fresh produce must be held between 32-39°F, a relatively small temperature window that doesn’t leave much room for error. When held within this range, lettuce would last approximately 15 days. But if holding temperatures veer above that setpoint during shipping, its shelf life can quickly be cut in half.
This means grocers could potentially receive a shipment of produce that’s already at the end of its useful shelf life — not to mention potentially spoiled or unsafe to eat — giving them fewer days to sell product before it would need to be replaced by the next shipment.
Temperature control for quality (TCQ) teams are dedicated to minimizing food shrink, preserving freshness, and maximizing the shelf lives of perishable products. Their programs are designed to monitor, manage and ensure temperatures are kept at precise (i.e., recommended) setpoints throughout every step of the cold chain journey.
Doing so requires coordination among every stakeholder and change of custody — from harvest to staging to shipping and storage. If temperature abuses occur at any point of the process, TCQ teams need to know the extent and duration of the excursions, so they can determine the impacts to food quality — and potentially safety.
The Food Safety Modernization Act (FSMA) requires producers and their carriers to agree on a method of temperature control. Upon request, they must be able to demonstrate that they have upheld their responsibilities of maintaining proper temperatures of a given perishable.
With these responsibilities and requirements in mind, stakeholders can adhere to established best practices for maintaining temperature certainty throughout the cold chain journey. When integrated into a robust quality control strategy, the following strategies can help to minimize temperature abuse and maximize perishable shelf life and quality.
1. Pre-cool after harvest. Prior to loading into a refrigerated trailer, temperatures should be lowered to the ideal shipping setpoints within pre-cooling sheds. This process will help to ensure that produce enters shipping containers at the proper temperatures. To start a record of cold chain custody, temperatures must be checked, verified and documented.
2. Check insulation on transport reefer trucks and trailers. With the proliferation of aging trucks used on the road today, proper insulation has become a major concern. Refrigerated trailers are designed to hold (not cool) temperatures. At typical deterioration rates, a 10-year-old truck may have already lost 50% of its insulative value, making it more prone to temperature excursions and resulting in unwanted temperature zones or inconsistencies within the trailer.
3. Run refrigeration in “continuous” mode only. To save money on fuel, some drivers will periodically run the refrigeration in “fuel saver” mode. Continuous mode is the best way to keep and hold the required setpoint temperatures throughout cold chain shipping. Thermistors on refrigerated trucks and/or trailers should be calibrated annually to ensure proper temperatures readings.
4. Load pallets correctly. Proper airflow is required to maintain consistent temperatures from the front to the back of trailers. Loading and locking pallets in a center-line configuration (i.e., off the trailer walls) provides proper airflow and promotes temperature consistency.
5. Optimize load transfers and receipts. Hand-offs and deliveries provide ample opportunities for temperature abuse due to the loading and unloading that typically occur. These transfers must be brief and conducted efficiently to limit open trailer doors or extended periods sitting in receiving docks, especially in warm months or regions.
6. Inspect trailers and product between loads and transfers. To maximize product quality, drivers and/or carriers need to maintain clean, contaminant- and odor-free trailers. Trailers should be inspected between loads and transfers and cleaned as needed to preserve load quality. Product should be pulp-tested to record and/or document temperatures at every transfer.
7. Avoid mixed loads with multiple temperature zones. Mixed loads, which contain a combination of fresh and/or frozen products with different ideal temperature setpoints, create significant temperature control challenges. Even in short trips from a distribution center (DC) to a store, where this is most common, product may be compromised. If this is a routine practice in certain lower-risk scenarios, TCQ teams should flag these shipments for closer inspection upon arrival to the retail outlet.
8. Monitor temperatures at every step. Temperature tracking and logging technologies should be implemented to help ensure compliance at each of these steps. Automatic data capture and temperature recording can be used to provide accurate reporting and verification — helping to settle disputes with objective facts. In addition, TCQ teams can leverage these technologies to notify stakeholders of potential temperature abuse via live alerts — enabling them to quickly take corrective or alternative measures. Finally, collective data analytics can be used to uncover carrier performance trends, trouble spots and issues related to temperature control.
Temperature tracking for a more reliable cold chain
Maintaining proper temperatures throughout the cold chain journey is imperative to preserving perishable quality and maximizing shelf life. Real-time trackers and cargo software and services can create the robust temperature-tracking infrastructures that food quality and safety teams need to manage their perishable cold chains.
