Cooling cooked and blanched foods is an area of particular interest for most food processors that incorporate pasta, rice, vegetables and dry beans into their food products. Cooling uniformity is critical to achieve a refrigerated, frozen or canned meal that will have the desirable texture and taste when it is later reheated by the consumer. The blanched pasta cannot be too stiff or too soft, and it cannot be stuck together or damaged. The cooked rice should keep its texture, have the right amount of free starch (for stickiness) and maintain its kernel integrity. Dry beans should not be bursting or split. And, vegetables should have the desired firmness and consistency. Regardless of the cooking or blanching method used, without a highly effective cooling capability, these products cannot be obtained with a high degree of uniformity.

Even more important, the rapid chilling of cooked product is an area of food production particularly beset with challenging temperature parameters that, if violated, can open the door to product contamination.

Bacteria like to grow in the “danger zone,” an environment between 40 and 140°F (4.4 and 60°C). During commercial cooking processes, raw ingredients are brought up above 140°F as quickly as possible to the final cooking temperature, thus minimizing the time that food products are kept in the danger zone. The same is true on the other end of the production line: reducing the temperature as quickly as possible through the danger zone to below 40°F is essential.

Several conditions are required to achieve a high level of product quality and maintain the assurance of product safety in a time frame compliant with USDA and FDA standards. They include:

  • Precisely controlling the temperature and time of the cooling cycle.
  • Ensuring the product is being cooled equally.
  • Ensuring proper agitation exists to keep the product separated but undamaged.

Cooling systems must successfully integrate these components to effectively deliver absolute uniformity in product cooling.

For many years, water-spray and airflow shaker conveyors and rotary rinse wheels were the standard for cooling cooked and blanched food products; however, each method has drawbacks. Overall, the chilling methods are only as good as their ability to stop the cooking process. Pasta, rice and other food products are moved on a conveyor or rotary wheel while a cold-water spray or chilled air is applied to the product stream to reduce its temperature after cooking. These systems are not capable of precisely controlling the time and temperature of the cooling process, and they do not provide uniform product coverage by the water spray or airflow. Also, they do not have a means of adequate agitation to keep the product separated. These factors limit their ability to uniformly halt the cooking process cycle. To thoroughly cool product from 200 to 40°F (93 to 4.4°C) may take as long as 20 min, and for much of this time, the product temperature is within the bacterial danger zone.

To address the limitations of other cooling systems, one company developed a cooling system with one, two or three cooling tanks connected in sequence. Products enter the system, developed by Lyco Manufacturing, through the top of the first tank and are fed through a chute or conveyor from the cooker. They then run through the first cooling chamber, exiting through the bottom of the tank, before being transported to the top of the tank via a pipe and onto a wedge-wire-screened dewatering chute.  At this point, products are chilled from 200 to 70°F (93 to 21°C). The food products can be exported to a conveyor for downstream processing or immediately continue into a second inline chamber, repeating the cycle and converting the temperature from 70 to 55°F (21 to 13°C). Finally, the food products can be exported or continue into a third inline chill tank to bring them below the bacterial danger zone temperature.

 The continuous-flow cooling system provides an opportunity for food processors to run their operations more efficiently. Effectively cooling food products through the bacterial danger zone quickly helps mitigate the risk of contamination.  

For more information from Lyco Manufacturing Inc., Columbus, Wis., call (920) 623-4152 or visit

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