Chilling in food processing and preservation

Chilling involves reducing the temperature of the food above the freezing point

1. CHILLING
GROUP ONE

2. THEORY OF CHILLING
uChilling refers to the process in which the temperature of the food is reduced
to a low temperature above its freezing point but below the ambient to slow
down microbial growth and the rate of chemical reaction in foods.
uIt causes minimal changes to sensory characteristic and nutritional properties
of food.
uTo effectively chill food it is important to store food at right temperature
range. Above freezing and below 15 degrees Celsius.
uchilling only slows down microbial growth but may not completely stop it
therefore it is important to follow proper food handling and storage practices.
uProper food handling and practices include, monitoring clean and hygienic
conditions, using proper packaging and adhering to appropriate time to ensure
food safety.

3. FACTORS TO CONSIDER DURING CHILLING
1. Temperature
uMicroorganisms grow best at temperatures above 15 degrees Celsius and below 8 degrees Celsius
the rate decreases.
uThe chilling temperature range is an important factor that inhibits microbial growth without
altering nutritional value of food.
2. Relative humidity of the environment
uProper humidity levels are crucial to prevent dry outs or excess moisture which can lead to
spoilage and microbial growth.
uHigh humidity in cold rooms should be avoided since condensation on the walls creates proper
environment for mold growth.

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3. Product type
uDifferent food products have varying composition, structures, and susceptibility to temperature
chance.
uFor example vegetables are more sensitive to temperature and may quickly lose texture and
freshness when exposed to temperature that are too cold hence they require precise control.
4. Storage conditions
uShelf life of the food can be extended considerably by modifying the temperature in the cold rooms.
uOverfilling of the fridge should be avoided to maintain proper ventilation and temperature control.
uMaintaining appropriate humidity and airflow helps prevent moisture loss which can lead to food
spoilage.
5. Airflow or air velocity
uadequate air flow can help prevent condensation build up on chilled item. Condensation can lead to
moisture related issues like spoilage.
uOptimizing airflow can improve the efficiency of chilling systems by ensuring that all parts of chilling
area
uProper airflow management during chilling helps maintain quality and freshness of the chilled items
by preventing fluctuation and ensuring uniform cooling.

5. EQUIPMENTS FOR CHILLING
1. Refrigerators
uThis is the mostly widely used equipment for chilling food in commercial kitchen and commercial
food establishers.
uThey use a refrigeration cycle to remove heat from the air inside and maintain a low temperature

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2. Blast chillers
uBlast chillers is used in commercial kitchens and food processing facilities.
uThey rapidly cool or freeze food products by circulating chilled air over them.
uThey maintain the quality and safety food by quickly bringing down temperature and bringing down
the temperature preventing the growth of bacteria.

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3. Cold rooms
uThey are large insulating rooms that can be temperature controlled and can be similar to walk in
coolers.
uThey are essential for small scale storages large quantities of food at chilling temperature.

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4. cryogenic chillers
uThese use liquefied gases like nitrogen or carbon dioxide to rapidly cool the product to there
desired temperature.
uParticular useful for quick chilling and larger scale operations.

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5. Evaporative coolers
uThese use the evaporation of water to cool the air, which in turn chills the food products.
uThey are eaten used in conjunction with other chilling systems to maintain the delivered
temperature.

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7. Cold storage containers
uCold storage containers also known as reafers, are specialized shipping containers equipped with
refrigeration units
uThey are used for transportation and temporary storage of chilled or frozen foods over long
distance.

11. EFFECTS OF CHILLING
1. Texture change
uChilling process can affects the texture of foods.
uFor example freezing can make fruits and vegetables mushy when they are thawed.
uMeat and poultry can become tough and dry when chilled for long.
2. Nutritional quality
uChilling can preserve the nutritional quality of foods by slowing down the degradation of vitamins
and antioxidants.
uAlthough chilling can cause loss of nutrients in certain types of food for example vitamin A and C
are sensitive to light and high temperature.
uProlonged chilling can also lead to loss of nutrients in vegetables and fruits.

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3. Moisture loss
uProlonged chilling can cause certain foods to loose moisture, leading dryness and dehydration.
uThis is particularly true for foods with high water contents such as fruits, vegetables and meat.
4. Biochemical changes
uChilling can affects the biochemical composition of food including the levels of bioactive
compounds like antioxidants.
5. physiological changes
uFor fresh produce, chilling can slow down physiological processes like respiration and ripening,
which can maintain freshness.

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6. Spoilage
uWhile chilling can help preserve foods and prevent spoilage, excessive chilling or extended storage
periods can increase the risk of spoilage and microbial growth.
uThis can result in food that is spoilage, discolored or has unpleasant odor.
7. Microbial growth
uChilling slows down the growth of microorganism, which can cause spoilage
8. Flavor change.
uCooling can affects the flavor of certain food such as fruits and vegetables.
uFor example chilling can make tomatoes loose their natural flavor, while sweet fruits may become
less sweet.
uThe flavor of some species and herbs may also be affected by regrigeration.

14. CONCLUSION
uIn conclusion the chilling process plays a critical role across diverse industries, from
food processing to pharmaceuticals and beyond.
uBy employing effective chilling techniques, business can uphold product quality,
extends shelf life and ensures food security.