Removal of heat or lowering the temperature is one of the most used techniques to preserve or process food. When a food is subjected to a lower temperature, the biochemical and microbiological activity slows down, thus lengthens the food’s shelf life. The advancement in the food industry, especially during the late 21st century has allowed us to produce high-valued food products. The use of low temperature processes is continuously evolving.
Freezing, freeze drying, modified-atmosphere storage and packaging, and chilling are the most commonly utilized ways to process foods today. Among these, chilling is still the most important method of food production and preservation as more recent developments in minimal food processing rely on it.
Minimally processed food is a relatively new market trend that aims to produce high quality food products (longer shelf-life, less on chemical preservatives, and nutrient retention). The demand for safe, nutritious, and ready-to-eat food products are at its highest. New technologies have aggressively advanced to improve this market segment.
WHAT IS CHILLING?
Health-wise, people perceive chilling as the most friendly way of preserving food, especially fruits and vegetables. Freezing, on the other hand, usually results in quality loss due to lower temperature. In chilling, the food is stored at a temperature between 1ºC (39ºF) and 8ºC (46ºF). This temperature range results in little to no changes in the nutritional and sensory value.
This preservation method is one of the most used since the first chilled food items (meat and pies) was served in the 1960s. Since then, a wider range of food items has been kept chilled. Pizzas, sandwiches, salads, and dairies are favorites.
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Nowadays, many food items are heavily reliant to chilling, particularly fresh fruits and vegetables, fresh seafoods, and meat. “Ice slurry”, a mixture of crush ice and seawater, is typical for fresh seafood.
Bigger scale of operation typically used advanced chilling equipment— mechanical refrigerators and cryogenic chillers.
Chilled foods are grouped into three based on their temperature range.
| CHILLING TEMPERATURE | FOOD PRODUCT |
| -1ºC (30ºF) to 1ºC(34ºF) | Fresh fish, breaded fish, smoked meat, ground meat, meat, and sausages |
| 0ºC (32ºF) to 5ºC (41ºF) | pasteurized canned meat, milk, cream, yogurt, prepared salads, sandwiches, baked goods, fresh pasta, fresh soups and sauces, pizzas, pastries and unbaked dough |
| 0ºC (32ºF) to 8ºC (46ºF) | fully cooked meats and fish pies, cooked or uncooked cured meats, butter, margarine, hard cheese, cooked rice, fruit juices and soft fruits |
The booming market for convenience stores in the fast-pace world have also proven that chilling is a necessity. Convenience store chains like 7/11 and Tesco Express have chilled food for convenience for individuals who are always on the go.
HELPFUL TIPS DURING CHILLING FOOD ITEMS
Unlike freezing, which requires lower temperature, chilling needs close monitoring as the temperature is near the temperature danger zone (TDZ). TDZ is the temperature range between 4.4°C (40°F) to 60°C (140°F) where disease-causing bacteria grow best.
Remember that low temperature temporarily slows down biochemical and microbial activity. Any increase in temperature may increase the rate of spoilage of food.
- Storage devices such as display chillers must be well-monitored for anything crucial that may promote microbial growth. For example, the built-thermometer must be working, but it may not be properly calibrated to show the correct temperature inside. This is particularly important for low acid chilled foods, which are particularly susceptible to microbial contamination.
- Chillers must have a built-in thermometer for ease of temperature monitoring. Regular temperature monitoring is a must. In the industrial setting, this is practiced with a checklist for religious monitoring. Also, the environment (from the manufacturing facility, during transport, at stores) for chilled products must be hygienic at all times.
- Never overload the chiller or cooler, no matter what. Cool air should circulate freely to cool the foods. If the area is full, you are just spending more money for making the refrigeration system work harder. Or worst, the equipment may break down sooner.
Check out more refrigeration food safety tips for your home.
These are simple operating procedures, but have been proven to have saved the global manufacturing and distribution chain a huge amount of money. A good way to lessen the food loss due to spoilage, which contributes to a loss of $35 billion a year globally.
You may want to read more about refrigeration and food safety from USDA
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