The meat's condition before freezing, the packaging material, method and rate of cooling and freezing, and the temperature during storage are all important. So, too, is careful thawing and skilful cooking.
Packaging
- Packaging must be moisture-proof so moisture is sealed in.
- Meat should be packaged in sturdy, freezer-quality, oxygen impermeable plastic bags. The air must be extracted and the bags tightly sealed.
- Vacuum packaging is preferred. Any air left between the meat surface and packaging encourages deterioration in quality.
- Poor packaging or punctured packaging leads to development of freezer 'burn' (surface drying and discolouration).
Storage temperatures for frozen meat
- Freezer temperatures should be maintained at - 18*C.
- Avoid fluctuation in temperature where possible.
- Frozen packs should be arranged to ensure good air circulation.
The freezing process
- Meat should be frozen fast, in small lots. This is important.
- Blast freezing is ideal, which lowers temperature extremely rapid.
- Slow freezing causes large ice crystals to form. These can rupture the meat cells and, on thawing, cause excessive loss of juices.
- The size and shape of the meat to be frozen is important: small, flat packages freeze more quickly that large joints.
- Free-flow freezing steaks or small cuts should be spread in a single layer on clean, foil-lined trays. Cover with a sheet of foil and freeze. As soon as they are frozen solid, pack the cuts in freezer- quality bags, extracts air and seal from drying. promptly return packs to the freezer.
Hints on Freezing
- Before freezing, beef or lamb should be sufficiently aged, as meat does not continue to tenderise when frozen
- Meat shoul be well trimmed (fat can become rancid on large storage) the ends of bones which may pierce the wrap should be shielded (e.g with foil or plastic) before packaging.
- Frozen large cuts will keep better, longer, than frozen small cuts, thin slices or mince.
- Again, it is important to ensure temperatures don't fluctuate by more than 0.5C. Big temperature changes can mean a partial thaw, which damages the structure of the meat.
Thawing
If at all possible, plan ahead when you intend using frozen meat. The best way to maintain quality of frozen meat is by slow thawing in the refrigerator or chiller, in its original wrapping. Ensure there is no possibility meat drip during the thawing can contaminate other foods. For example, thaw meat on a tray if there is a chance the packaging may leak.
Thawing meat at room temperature is not recommended. The meat surfaces may reach warm temperatures that encourage microbial spoilage. The higher the temperature above freezing, the faster the microbial growth. Temperatures above 7C are especially dangerous as they allow the growth of pathogens such as Salmonella, if they are present on the meat.