Food preparation and processing is where many hazards are controlled, or created. Thawing, cooking, cooling, cook-chill and cook-freeze must all be done correctly, every time.

This module explains how to process food safely, how to hold and reheat it, and how to take accurate food temperatures.

Many of the critical control points on a food manufacturing site are found in processing. This module covers:

• Thawing frozen food.
• Cooking, and core temperatures.
• Taking food temperatures.
• Hot holding and reheating.
• Cooling.
• Cook-chill and cook-freeze.
• Avoiding cross-contamination during processing.

Thaw frozen food completely before cooking it, so that the centre is fully defrosted. If food is still partly frozen, the centre may not reach a safe temperature during cooking, and harmful bacteria can survive.

Thaw food under temperature control, ideally in a dedicated thawing chiller. Keep it covered, and away from ready-to-eat food, so that drips cannot contaminate anything.

Never refreeze raw food once it has thawed.

Cook food to a core temperature of 75°C, or an equivalent time and temperature, such as 70°C for 2 minutes. The core is the slowest-heating part of the product, and it must reach the target.

In manufacturing, the cooking process is usually a critical control point. It must be validated, to prove it works, and then monitored and recorded for every batch.

If a batch does not reach the critical limit, follow the corrective action, and tell your supervisor.

Use a clean, calibrated probe thermometer, and check the core, or centre, of the product. This is the slowest part to heat up or cool down.

Clean and disinfect the probe before and after each use, to avoid cross-contamination. Probe wipes are often used.

Probes must be checked regularly for accuracy, for example in iced water, which should read close to 0°C, and in boiling water, which should read close to 100°C. Report any faulty probe straight away.

Hot food that is held for service or display must be kept at 63°C or above.

When food is reheated, it must be heated thoroughly, until it is piping hot all the way through, to a core temperature of at least 75°C.

Food should only ever be reheated once. Each time food is cooled and reheated, it passes through the danger zone again, and bacteria have another chance to grow.

Cool cooked food as quickly as possible, and put it in the fridge within two hours. Slow cooling allows bacteria and spores to multiply.

To speed up cooling:

• Use a blast chiller, or a dedicated cooling area.
• Spread food into shallow trays.
• Divide large batches or joints into smaller portions.
• Never put hot food into an ordinary chiller, where it can warm up other food.

Cook-chill means cooking food, then chilling it rapidly to between 0°C and 3°C, for storage and reheating later.

Chilling must be fast. Start chilling within 30 minutes of cooking, and bring the food down to 3°C or below within a further two hours. Keep it at 0°C to 3°C through storage and distribution, without a break in the cold chain.

Cook-chill food must be clearly labelled with its use-by date, and reheated thoroughly before it is eaten.

Cook-freeze means cooking food, then freezing it rapidly to -18°C or colder, for longer storage.

Fast freezing protects both quality and safety. Freezing does not kill bacteria, so the food must have been cooked and handled safely before it is frozen.

Label and date frozen product, rotate stock, and make sure it is thawed and reheated correctly when it is used.

• Keep raw and ready-to-eat food apart, with separate equipment, staff and areas, such as high-risk and low-risk zones.
• Follow the colour coding for equipment, utensils and protective clothing.
• Control allergens, and follow the production schedule.
• Wash your hands between tasks, and when you move between areas.
• Clean as you go, and clean and disinfect equipment between products.
• Never take equipment from a raw area into a ready-to-eat area.

To process food safely:

• Thaw food completely before cooking.
• Cook to a core temperature of 75°C, or an equivalent.
• Use a clean, calibrated probe to check temperatures.
• Hold hot food at 63°C or above, and reheat only once.
• Cool food rapidly, and refrigerate it within two hours.
• Follow the cook-chill and cook-freeze controls.
• Avoid cross-contamination at every step, and record your checks.