Refrigeration utilized to preserve foods dates back to prehistoric times. At the time, folks used snow and ice to store looking hunting. Slow freezing was risky; it was not until the twentieth century that the commercialisation of frozen foods began with the invention of a speedy freezing method: the deep freezing.
In order to achieve a negative core temperature for preservation, there are two options: freezing or deep freezing.
FREEZING
Freezing may be a technique that involves a slow decrease (up to 24h) in temperature. The water contained in product is transformed into massive ice crystals. This method is employed by private individuals WHO keep their food stored in the freezer.
Disadvantages: the perimeters of the crystals will find you perforating the food cell wall. Elements of the water and therefore the most volatile aromas will evaporate. Disorganization of structural tissues will cause enzymatic and non-enzymatic reactions that alter texture and flavours of the food product. Also they have a tendency to dry out.
DEEP-FREEZING
Deep-freezing is an industrial technique that involves cooling quickly and viciously (a couple of minutes to an hour) food by exposing them intensely to temperatures from -30 ° C to -50 ° C, till the product core temperature reaches -18 ° C. With this method, the water contained within the cells is finely crystallized. The killing of cells and also the proliferation of microorganisms are restricted. The cells become dormant as results of the low-temperature. Therefore the products treated retain their freshness, textures and flavours keeping their essential nutrients and vitamins.
To ensure optimum efficiency, deep-freezing equipment should be custom-made per the frozen foods. It’s so necessary to look at the freezing capability given on the info sheet of the deep freezing unit (deep-freezer, blast chiller for trays or trolleys, deep-freezing tunnel).
Deep freezing will cause serious sickness if the method isn’t performed properly, it’s so necessary to require various precautions to avoid this and to preserve the first quality of the products.
SAFETY PRECAUTIONS FOR DEEP-FREEZING
TEMPERATURE
Food must always be cooled to 4 ° C before being frozen to avoid increasing the temperature of the chamber and cause electrical consumption.
Once frozen, the products should be keep at a negative temperature variable from -9 to -18 ° C depending on the product. bear in mind to see the temperature and maintain your storage equipment.
HYGIENE
It is better to deep freeze a recent product instead of a product that has already began to spoil so as to preserve its qualities.
Basic hygiene rules still need to be adhered to even though we are operating with low temperatures for although there are fewer being or they become dormant some will survive at low temperatures. it’s thus essential to:
- Wash hands thoroughly and all food handling tools.
- Wash the products.
- Clean and disinfect the deep-freezer / storage system / cold room.
- Use sealed freezer bags or suitable containers to protect the food while taking care to air vacuum and carefully close lids or bags.
- Never refreeze a product that has been defrosted or during defrosting. Re-freezing a product which has been defrosted causes proliferation of bacteria. If they are pathogenic, they can cause food poisoning.
STORAGE TIME
The shelf life of frozen foods varies from one to twenty four months according to totally different food products. it’s thus essential to label them so as to not exceed the recommended expiration date.
- Here is the best use before dates for the following food groups*:
- Fruits and vegetables: 24 months
- Pre-cooked potato products: 24 months
- Meat and poultry, whole or in portions: from 15 to 18 months
- Minced Meat: 12 months
- Sea food fished or farmed: 24 months
- Fatty fish: from 9 to 10 months
- Breaded Fish: 24 months
- Baked pastries, doughs and Viennese pastries: 12 months
- Raw Viennese pastries: 24 months
- Ready meals: from 18 to 24 months
- ice creams and sorbets: from 18 to 24 months
DEFROSTING
Defrosting allows, by gradual warming, a frozen product to come back to its original state. Throughout the increase in temperature, microorganisms can get up and multiply. From -18 ° C to -2 ° C, microbial hazards are close to zero. Established on the products, it’s suggested:
- To defrost products at a temperature below 4 ° C than at room temperature where bacteria multiply rapidly.
- Or cook it directly without defrosting.
We at KERONE have a team of experts to help you with your need for deep freezer in various products range from our wide experience.