DEFROSTING

Some foods taken from the freezer can be cooked immediately but poultry, joints of meat and other large items must be completely thawed before cooking. If food is not completely thawed, ice is likely to be present at the centre and the heat from subsequent cooking will be used to melt the ice and not to raise the internal temperature above that required to destroy pathogens. Inadequate thawing of poultry frequently results in undercooking and subsequent food poisoning.

Thawing of frozen poultry must be carried out in cool conditions because, at room temperatures, bacteria will multiply on the warm surface of the food whilst the centre remains frozen. Thawing is best carried out at 10°C to 15°C in an area entirely separate from other foods, or in a thawing cabinet. If thawing is to be undertaken in a refrigerator (below 8°C), it must be appreciated that it will take much longer.

The use of microwave ovens may lead to some parts of the food cooking before the whole mass of food is thawed because areas that thaw absorb energy preferentially to areas which remain frozen.

Rules for handling frozen poultry:

water is preferable to thawing in warm kitchen temperatures or in refrigerators with limited space. Poultry will be ready for cooking when the body is pliable, the legs are flexible and the body cavity is free from ice crystals.

COOKING

The law requires that cooked high risk foods are sufficiently heated to destroy food poisoning bacteria. As part of your hazard analysis, the cooking of high risk foods would be a critical control point, therefore, under the Food Safety (General Food Hygiene) Regulations 1995, a control must be implemented and monitored to ensure its effectiveness.

Different methods of cooking eg: roasting, boiling, deep fat frying, may require different controls and methods of monitoring.

Roasting
Whole joints of beef or lamb (i.e. not boned and rolled), may be cooked rare. This is because bacterial contamination is found on the surface of the meat only where it should be destroyed quickly during cooking.

Where bacterial contamination may be present in the core of the meat/meat product the core temperature should be checked with a sanitised probe thermometer. The required core temperature at completion of cooking is a minimum of 75°C (or equivalent). It is recommended that temperature checks are recorded.

To allow for thorough cooking, it is recommended that the joints do not exceed 2.5Kg (6lbs) in weight unless specialised equipment is available to achieve suitable temperatures.

Boiling
Foods which are cooked on the hob, eg. curries, stews etc, will be boiled, simmered and stirred for some time. As the cook temperature should reach 100°C throughout the food it should not be necessary to temperature check these dishes. It is however important to stir these foods well during cooking to avoid any cold spots.

Deep-Frying
Provided these foods are cooked in fat at the correct temperature and for sufficient time, then a lower risk is presented. It is, however, still possible to undercook especially if the item is cooked from frozen and the fat is too hot.

Standardising the Cooking Process
The cooking process for foods which are always the same shape, weight and size can be “standardised” so that only random temperature checks with a probe thermometer will be necessary. The core temperature achieved in cooking the food for a set time at a set oven temperature can be checked a number of times using a probe thermometer to ensure it exceeds 75°C. Then assuming the cooking process remains constant for that food, random checks may then be made thereafter.
If the probe is inserted into food, the probe must be sanitised before and after each use.
Digital probe thermometers are recommended.

It is recommended that records are kept of cooking temperature checks and of any assessment made in standardising the cooking process.


HOT-HOLDING

The law requires that foods being held hot, are held at temperatures above 63°C.
It is the food temperature which is critical and not that of the unit.

If hot, high risk foods are held, on display, at temperatures below 63°C, then you must be able to prove:

Open foods on display should be protected, as far as possible, from any form of contamination. Sneeze screens are good practice to prevent the foods from contamination from customers.

COOLING

The law requires high-risk foods, which have been cooked and are not for immediate consumption, to be cooled to below 8°C as quickly as possible.
As part of your hazard analysis “cooling” of high risk foods would be a critical control point and, therefore, under the Food Safety (General Food Hygiene) Regulations 1995, a control must be implemented and monitored to ensure its effectiveness.

Spore-forming bacteria, are present in many foods, and survive conventional cooking. Spores themselves are not harmful, however they will germinate and become harmful if left in favourable conditions, e.g. when foods are left in the “danger zone” between 8°C and 63°C, for long periods of time.

Methods of speeding up cooling.

As a general guidance foods should not remain in the “danger zone” (e.g. 8°C-63°C) for longer than 4 hours. The maximum recommended times are:

REHEATING

The law requires that, where necessary, foods are reheated thoroughly to ensure the destruction of food poisoning bacteria.
As part of your hazard analysis, the reheating of high risk foods may be identified as a critical control point, and if so, under the Food Safety (General Food Hygiene) Regulations 1995, a control must be implemented and monitored to ensure its effectiveness.

If there is a chance of bacteria surviving an earlier cooking process, that bacterial spores have germinated during cooling, or that food has become contaminated in any way after cooking, then reheating will be critical to food safety and the food must be reheated to a temperature of 75°C, or equivalent.

Where food has been thoroughly cooked, cooled quickly and is refrigerated at an appropriate temperature until use, bacterial growth should be minimal. In such cases reheating should not be a critical control point, but reheating the food until it is piping hot right through provides an additional safeguard.

Foods should not be reheated a second time.

This Guidance Sheet contains basic information only. For more detailed and authoritative advice you should refer to the relevant Industry Guide to Good Hygiene Practice available from the Environmental Health Department on 823000.