HACCP for Frozen Foods: Thawing, Storage & Temperature

All frozen foods must be stored at -18C or below. This is both the UK legal requirement and the international standard. At -18C, microbial growth is halted (though not all organisms are killed), and enzymatic degradation slows significantly. Monitor freezer temperatures continuously if possible, or at minimum twice daily with manual checks, recording readings on your temperature log. Install a high-temperature alarm set to trigger at -15C, giving you warning before temperatures reach critical levels. On delivery, frozen goods should arrive at -18C or below. Reject any frozen delivery that has clearly thawed and refrozen (indicated by ice crystal damage, frost-free packaging in a frosty environment, or products stuck together in clumps). Check core temperature of representative items using a between-pack probe or a probe designed for frozen products - surface temperature alone is unreliable. Once accepted, transfer to your freezer within 15 minutes. Stock rotation is critical: use first-in, first-out, and label all items with the date of receipt. While commercially frozen products have long shelf lives, quality deteriorates over time. Follow manufacturer guidance for maximum frozen storage periods.

The question of whether food can be refrozen is one of the most commonly asked in food safety. The general rule is: do not refreeze raw food that has been fully thawed, because each freeze-thaw cycle allows a period of microbial growth in the danger zone, and the cumulative effect can reach unsafe levels. However, food that has been thawed, cooked to 75C, and then cooled properly can be frozen as a new product (for example, raw chicken thawed, cooked into a curry, cooled, and frozen). Many products are designed to be cooked from frozen - frozen chips, breaded fish, vegetables, and some prepared meals. When cooking from frozen, the critical control is ensuring the core reaches 75C despite starting from -18C. This often requires longer cooking times and should be verified by probing the core temperature. Oven temperature alone is not reliable for cook-from-frozen items, as the exterior can reach safe temperatures while the core remains in the danger zone. Monitor your freezer with a calibrated thermometer (ideally a data logger for continuous recording) and include freezer temperature checks in your daily opening and closing procedures.