When it comes to refrigeration in a kitchen, there are many areas to look into. With HACCP (Hazard Analysis Critical Control Point), the systematic preventive approach to food safety, ensuring food is safely cooled is imperative. This brings us to introducing blast chillers into a kitchen to safely cool food.
Reducing Temperatures with Blast Chillers
Blast chilling is a method of cooling food quickly to a low temperature that is almost entirely safe from bacterial growth. Blast chillers use blasts of cold air to quickly freeze or chill its contents. Bacteria multiply fastest between +8 °C (46 °F) and +68 °C (154 °F). Unchecked, bacteria growth doubles every 20 minutes; in 12 hours, one bacterium has multiplied into 69 billion. By reducing the temperature of cooked food from +70 °C (158 °F) to +3 °C (37 °F) or below within 90 minutes, the food is rendered safe for storage and later consumption. This method of preserving food is commonly used in food catering and in the preparation of 'instant' foods, as it ensures the safety and the quality of the food product.
HACCP is the systematic preventive approach to food safety that addresses physical, chemical and biological hazards as a means of prevention rather than finished product inspection. This approach has significant benefits to organisations operating within the food supply chain as it enables them to determine key controls over processes and concentrate resources on activities that are critical to ensuring safe food. Retailers, the food industry and Government in particular are concerned about ensuring that food is produced safely and that the consumer has confidence in the product. In the UK the 1995 Food Safety Amendment Regulations for the first time required manufacturers and providers to adopt HACCP to ensure food safety.
Protecting Food With A Blast Chiller
Once the food is cooked to perfection you don't want it to continue cooking when removed from the oven. A blast chiller stops the food from cooking further, retaining the required food quality, nutritional value, flavour and appearance.
Fridges and coldrooms are designed for holding previously chilled food, not chilling hot food. To put hot food in a fridge or coldroom already holding chilled food is extremely dangerous. The temperature of the fridge will rise, lifting the temperature of previously chilled food and risking bacterial contamination of all stock in the fridge.
Food safety is of utmost importance in all cook-chill systems. Almost all food is clear of potentially harmful bacteria when it has been cooked correctly. Bacteria will begin to feed and multiply on cooked food as it then cools down. The faster cooked food passes through this critical zone from hot to cold, the less chance there will be of bacteria growth. Keeping records of foods, their temperatures and the time it takes to chill or freeze them is an important part of HACCP - a process made easier using a blast chiller, according to manufacturers.
Using A Blast Chiller
It is important that food entering the blast chiller does not exceed a temperature of 90°C. When placing containers in the chiller, it is recommended that metal containers and trays are used as other materials such as plastic or polystyrene containers will act as an insulator and extend blast chilling times. Sufficient space must be left between products in order to guarantee a sufficient flow of cold air and ensure products are not in contact with the internal walls of the unit. Products that are more difficult to chill because of their composition and size should be placed in the centre of the unit.
Blast chilling data refers to standard products (low fat content) with a thickness below 50mm: therefore avoid overlaying products on trays or the insertion of pieces with a much higher thickness, as this will lead to an extension of blast chilling times. Always distribute the product well on the trays and in the case of thick pieces decrease the amount to blast chill. The chiller should be used for storage for short periods only. When removing any product that has undergone blast chilling, always wear gloves to protect the hands from cold burns