The storage of frozen food
At temperature of around -40°C, most frozen food should keep for several years with out noticeable deterioration. How ever, most catering and retail freezers operate at -18°C. At this temperature a gradual loos of flavour and a toughening of textures occurs. Above -10°C spoilage organisms commence growth and, together with enzymes, can cause serious problems including souring, putrefaction and rancidity.
All frozen food should be labelled and coded to enable tractability and recall in the event of problems.
Storage of frozen food at retail premises
To ensure that customers receive the best quality frozen food, managers must:
- only use reputable suppliers;
- reject deliveries above -15°C or which show signs of thawing or having been refrozen, for example, packs of peas which have welded solid;
- not allow frozen food to remain at ambient temperatures for longer than 15 minutes. Food will, of necessity, be at ambient temperatures during unloading of deliveries and stocking display units from back-up stores;
- not use display freezers for freezing fresh food, as they are only capable of maintaining the temperature of the food which is already frozen;
- ensure that display units are not filled above the load line as this would result in thawing and deterioration;
- carry out regular inspections of freezers and check temperatures as least daily but preferably more frequently. Electronic probe thermometers, between the packs, should be used to ensure the accuracy of the indicating thermometers which should be fitted to all units in an easily readable position;
- ensure that back up stores are fitted with strip-curtains or air blowers and the doors are opened as little as possible to avoid unacceptable fluctuations of temperature. Ice build-up on the walls or floor of units must not be allowed;and
- implement effective systems of stock control and stock rotation. It is advisable to code food on delivery to assist rotation.
All food must be suitably wrapped in moisture-impermeable film to prevent drying out of the surface (freezer burn). Separate freezers should be used for raw and high-risk food.