Food begins to decay as soon as you take it out of its natural environment. Correct storage conditions can reduce the rate of decay so that food retains its texture, nutritional value, appearance and taste. It is vital that food is stored at the correct temperature, as failure to ensure this may result in food spoilage and problems of food fitness, in addition to the obvious reduction in shelf life. Correct storage is essential to any hygienic operation.

Inadequate temperatures will allow pathogens and bacteria to multiply within the refrigerator. The resultant food will contain pathogens and bacteria, exposing consumers to unacceptable and unnecessary risks.

During storage, foods must not be exposed to contamination, for example from foreign bodies, chemical agents, physical contaminants and microbiological organisms. A hygienic and clean environment is important to prevent these forms of contamination. Prevention of these contaminants depends on removing the sources or putting barriers between them and the contaminants. Thus human access with food must be restricted, food handling should be minimised, hygienic practices must be put in place, vermin must be excluded, and there must be separate areas for dirty and clean processes and raw and cooked meats. The routes of contamination must be disrupted by clean and hygienic practices.

Refrigerator Use

The normal recommended refrigerator temperature is between 1-4 degrees C for high risk foods. Refrigeration is a form of delaying and not preventing food spoilage.

Refrigerator Tips

The location of the refrigerator is important:

• Keep away from any heat source.
• Place in a well ventilated area.
• Ensure it is readily accessible.
• Hot foods should be cooled prior to placing them in the refrigerator.
• It is preferable to have separate refrigerators for raw and cooked meats in commercial premises. If this is not possible, raw meats should be stored underneath cooked foods to avoid any cross contamination of raw drips.
• Cleaning of the refrigerator must be regular.
• Foods must not be stored in cans except for unopened canned meats: these require only a few hours chilling to facilitate slicing.
• Containers must be food grade and covered.
• Temperature records should be taken throughout the day.

Temperature Monitoring

Refrigerator temperatures should be checked using an accurate digital or infra red thermometer. Infra red 'gun' thermometers are a non invasive method of taking surface temperatures. Temperatures in refrigerators (1-4 degrees C) and freezers (minus 18 degrees C) should be monitored and recorded. All temperature monitoring should be logged, usually in the morning, midday (busy period) and at the end of the day.

Probe Thermometers

Probe thermometers are commonly used in food premise:

They should be calibrated before use (iced water at 0 degrees C and boiling water at 100 degrees C are useful tests) to ensure accuracy.

Clean and disinfect probe thermometers in between each use to avoid cross contamination using a disinfectant wipe before and after use.

Also, when using the thermometer, ensure that it is probed into the correct depth to ensure that the temperature is taken from the centre of the food.

Freezer Use

Freezing of food will not improve food quality - it will reduce the time it takes for the food to decay. Some bacteria in frozen foods are killed when frozen but many survive and become dormant and will revive when thawed. Some organisms are active at well below 0 degrees C.

Freezer Tips

• Food should be placed in the freezer immediately on delivery.
• Freezer space should be sufficient to prevent overloading.
• 'Display type' freezers have a maximum load line, which should not be exceeded.
• The freezer should be located away from heat sources such as cooking or heating equipment and not exposed to direct sunlight.
• A system of stock rotation must be operated.
• Deliveries of frozen food must be checked to ensure that food is still frozen; it has become common practice to reject deliveries above minus 18 degrees C, although minus 12 degrees C is sometimes judged to be the absolute limit for acceptance of deliveries.
• Damaged packaging of frozen food may lead to freezer burn.
• Generally most meats, fruits and vegetables may be kept for 9-12 months and other foods 3-6 months, following manufacturers instructions.
• Re-freezing of thawed food even if this has been cooked is not advisable, since the numbers of bacteria increase through each freezing and thawing cycle.

Staff tasks

Staff should be given instructions on how to use the refrigerators and freezers and shown how to fill the temperature log sheets in correctly. Any spillages must be cleaned up immediately.

Thawing of food

Most food taken from the freezer can be cooked immediately but poultry, joints of meat and other large items must be completely thawed before cooking. If the food is not fully thawed and ice is probable at the centre and cooking takes place to melt the ice, it will not raise the internal temperature above the danger zone to destroy bacteria. If food is to be cooked, adequate thawing is vital to ensure that the heat of cooking can kill any pathogens and is not wasted in melting ice.

Thawing of poultry raises several problems and inadequate thawing frequently results in undercooking and subsequent food poisoning. Thawing of poultry is best carried out at 10 degrees C to 15 degrees C in an area entirely separate from other foods.

Microwave thawing has its disadvantages of producing localised hot or cold spots. It must be done on the correct settings following the manufacturers recommendations and can be very effective.

Stock Rotation

A good stock rotation system is important to avoid food waste and spoilage. Ensure that older food is used first ('first come, first served') - this applies to all types of foods. Regular daily checks should be made on short life perishable foods ie meats, fish, soft cheeses, pastry, dough products, some fruits and vegetables stored in refrigerators.

Refrigerators should not be overloaded, and food should be covered in a manner which allows good air circulation. Foods should be located at the front of the refrigerator, as this reduces the efficiency. Good stock rotation is essential to avoid any food spoilage.

Cooking Food

If fresh food is cooked thoroughly, at the correct temperature, for the correct amount of time and served immediately, this should never cause food poisoning due to bacterial growth. If the food is cooked thoroughly, this should ensure that all bacteria in and on the food should be destroyed.

The safest way to cook food is to use the short, high temperature method; which means that the food is quickly taken through the danger zone to reach a temperature at which the death of bacterial cells starts to occur. To ensure that bacteria are destroyed, cooking times and temperatures must be carefully calculated.

It is important to realise that cooked food may cause problems if it is allowed to cool too slowly.

Cooling Food

Cooked food required for cold service, after cooking, should be cooled to a temperature of 10 degrees C, or placed in a cooler 90 minutes before refrigeration, to avoid the multiplication of bacteria which have survived the cooking process, or the germination of spores which have not been destroyed through the cooking process. Larger portions of food can be cooked in smaller pieces.

Re-heating Food

Re-heating foods is a common cause of food poisoning. Problems occur when food is not sufficiently heated to the correct temperature, particularly where food had not been cooked, cooled or stored adequately. As a general rule, food which has been refrigerated or frozen must only be reheated once, to above 63 degrees C (75 degrees C at the centre is preferred) or until it is 'piping hot.'

Hot Holding

Equipment with a heated metal cabinet and shelves keeps food hot while it awaits service. Food temperatures in these should be above 63 degrees C and the cabinet temperature over 80 degrees C. These cabinets are not suitable for reheating food, their primary use being to hold the temperature of the food above the 'danger zone'. The danger zone is the range of temperatures around 5-63 degrees C in which food poisoning bacteria will multiply.

Hot Holding Requirements:

• Food Safety (Temperature Control) Regulations 1995.
• Food to be kept above 63 degrees C.

This includes food for service or display but excludes food which has been at less than 63 degrees C for a one off period of up to two hours.

No person shall in the course of a food business keep any food which:

• Has been cooked or reheated.
• Needs to be kept hot in order to control the growth of pathogenic micro-organisms or the formation of toxins.

Chilled Display Cabinets

Display cabinets must comply with certain specifications. They should be loaded correctly and only with chilled products. Radiant heat can have a significant effect on food stored here, with particular attention to the upper shelves where air temperatures may vary from 1.5 degrees C at the back to 6.5 degrees C at the front. Cabinets should not be located near a heat source and out of direct sunlight.

Foods likely to support the growth of pathogens should not be kept above 8 degrees C.