Advice for School Kitchen

Preparing meals for tens or even hundreds of students at an on-site kitchen is not an easy task as it can impose food safety hazards. During bulk cooking, heat from the heat source may not be evenly distributed in the food, resulting in food that is not thoroughly cooked or warmed enough before consumption. Cooking of food in large quantities can often result in food staying within the Temperature Danger Zone (4-60°C) for long periods of time before consumption, allowing foodborne pathogens to thrive. Cooling down large amounts of food can also be problematic, as heat trapped deeply within the food may not escape quickly enough, resulting in bacterial growth in food. Furthermore, poor hygiene practices and a lack of kitchen space can increase the risk of cross contamination between raw and cooked food. Therefore, trained manpower as well as adequate room for purchasing, storing, preparing, cooking and distributing food at a school kitchen are crucial.

If schools serve meals from on-site kitchens, they should ensure that the kitchen is sufficiently large, well-equipped, regularly maintained and hygienic, and the staff who prepare and handle food are supervised, instructed and trained in food hygiene practices. The following simplified guide is adopted from the "Safe Kitchen: An Illustrated Guide to Good Hygiene Practices for Food Handlers", covering GHPs necessary for working in a kitchen. All food handlers are advised to go through the materials before work.

A) Purchase

• Purchase food ingredients from licensed and reputable suppliers.
• Purchase food ingredients that are fresh and wholesome.
• Avoid any raw or undercooked food as they are high-risk foods with no or inadequate heat treatment involved to eliminate the microorganisms present.

B) Receiving and Storage of Raw Materials

• Check food for its quality, appearance, expiry dates,labelling and package integrity upon arrival and prior to storage. Check for any signs of infestation. Dispose of any suspicious foods that could compromise food safety.

• Store perishable foods, such as raw meat, pasteurised milk and cheese, in a refrigerator immediately after checking is completed.

• Store raw foods separately from cooked and ready-to-eat foods to avoid cross-contamination.

• Store food items to be kept at room temperature, such as canned food, cereals and potatoes, in a cool and dry place.

• For prepackaged foods, follow the storage instructions on the package.

• Practise an effective stock rotation system, e.g. the first-in-first-out principle.

• Store chemicals and cleaning equipment away from food storage areas.

C) Preparation

• Ensure that adequate facilities such as wash basins, refrigerators, cutting areas, defrosting areas or cooking appliances are available in the kitchen.
• Use separate food preparation areas to handle raw, cooked and ready-to-eat foods. No unauthorised switch of area use should be allowed. If raw, cooked and ready-to-eat foods need to be handled in the same preparation area, disinfect the area thoroughly between uses.
• Should washing raw meat or poultry be needed, clean and sanitise the sinks and the surrounding areas afterwards.
• Use designated tools and utensils, e.g. chopping boards and knives for handling raw and cooked/ready-to-eat foods.
• Fruits and vegetables should be washed thoroughly under clean running water before preparation. Scrub hard surfaces of produces, such as melons, with a clean brush to remove dirt and contaminants.
• Keep chilled (perishable) food out of the refrigerator for as little time as feasible during preparation.
• Defrost frozen foods in a refrigerator at 0-4°C, in a microwave, or under clean and cool running water. Food defrosted by the latter two methods should be cooked immediately after defrosting. Do not defrost food at room temperature. Except for food properly defrosted in the refrigerator, refreezing defrosted foods is not acceptable.

D) Cold Storage

• Perishable food should be wrapped or put into an airtight container, and stored at the correct temperature:
  • Chilled food: 4°C or below
  • Frozen food: -18°C or below
• Ideally, use separate refrigerators for raw foods and cooked foods. Otherwise, store cooked or ready-to-eat foods on the upper shelves of the refrigerator, and raw foods on the lower shelves.
• Transfer any opened foods into a clean container and mark them with the food name and the date of opening before keeping them in the refrigerator.
• Check and record the temperatures of the refrigerators twice a day.
• Do not overfill the refrigerator.

E) Cooking and Reheating

• Always cook or reheat foods thoroughly before serving. Using a food thermometer to ensure that the centre or the thickest part of the food reaches 75°C or above for at least 30 seconds.
• Reheat foods only once; do not refrigerate them again after reheating.
• Follow the cooking instructions on the food packaging, if present.
• Preferably adopt the "cook-serve system" (i.e. serve the food right after cooking) to shorten the preparation time.

F) Hot and Cold Holding

• Pre-cooked foods, especially rice, pasta, eggs, meat, poultry and gravy, should be stored properly in hot- or cold-holding devices within 2 hours of cooking if not served immediately.
• Preheat suitable hot-holding equipment before storing hot food ingredients. Food must be kept at temperatures over 60°C.
• Pre-chill cold-holding equipment before storing cold food ingredients. Food must be kept at 4°C or below.

G) Cooling

Cooked food, if not immediately consumed, should be cooled down quickly using safe chilling methods.

1. Two-stage Cooling Method

• Cooked food is divided into smaller portions and placed in shallow containers.
• Food is cooled down stepwise from 60°C to 20 °C within 2 hours, and then cooled further from 20°C to 4°C within 2-4 hours.
• A thermometer is used to ensure that the ice water temperature remains consistently at 4°C or below.
• An ice water bath, paired with stirring, can help to speed up the cooling process.

2. Blast Chilling Method

• Food is divided into smaller portions and placed in shallow containers before being rapidly cooled down to 4°C in a blast chiller within 90 minutes

H) Distribution

When portioning food on-site at school:

• There should be clean and adequate space, equipment (e.g. electronic warming devices or insulated containers) and designated utensils for portioning. Sufficient manpower should be arranged to portion and distribute meals efficiently.
• Cooking and portioning should be performed in separate areas.
• There should be a complete set of hand-washing facilities for food handlers.
• Kitchen staff appointed for portioning should wear hand gloves and change them when they are torn or soiled. Hair nets, aprons and masks may be worn as appropriate.
• Food temperature should be checked just before distributing meals to students. Hot food should be kept above 60°C while chilled food should be kept at 4°C or below. All foods, once portioned, should be consumed immediately and finished within two hours.
• Reusable containers and cutlery should be stored in sealed cupboards or containers that are rendered proof against dust and pests.

Whether schools choose to provide buffet meals to students regularly or on a one-off occasion, such as a party, they should ensure that:

• The warming devices and cold units are in good condition.
• The food temperatures are monitored; cold foods are held at 4°C or below, while hot foods above 60°C.
• Core temperature of foods displayed is checked using a clean probe thermometer regularly.
• Follow the 2-hour / 4-hour rule. Leftover foods are disposed properly.
• Food display at room temperature should be well covered.

Advice for Ordering Meals from Suppliers

Some schools place lunch orders for their students through an external meal supplier. When selecting a lunch meal supplier, schools should ensure that:

• The supplier has obtained a licence (“Food Factory (Approved to Supply Meal Boxes)”) issued by the Food and Environmental Hygiene Department (FEHD). Click here to find the list of licensed caterers.
• The supplier keeps a good food safety record as revealed by FEHD health inspectors’ inspection record to the supplier regularly.
• The choice of food, preparation standards, temperature control during the processes and delivery, food storage method and lunch box distribution are clearly stipulated in the contract. The supplier should monitor the aforementioned items properly to guarantee that they comply with the contractual requirements.
• The supplier observes proper hygiene practices during production by visiting their premises during the peak hours of operations before placing a long-term order for lunch boxes.
• Additional establishment, monitoring and record of procedures on food safety management with certifications, such as Hazard Analysis and Critical Control Point (HACCP) or ISO 22000 are in place.
• The holding temperature of meals is properly monitored during delivery of lunch boxes by the supplier.
• Maintain good communication with the delivery service provider to minimise the time in which the food is exposed to dangerous temperatures. Electric warming trolleys can be used to keep food consistently hot before use. When the meals arrive, distribute and consume them as soon as feasible.

Advice for Students Bringing Their Own Lunch

For parents or caregivers who prepare meals at home for their children to bring to school, they should:

• Observe the "Five Keys to Food Safety" in the course of preparation and transportation.
• Choose nutritious ingredients and use recipes that allow for safe storage in appropriate insulated containers.
• Pack meals right before leaving home.
• Keep packed meals at safe temperatures:
  • Pack hot meals into appropriate insulated containers, such as vacuum flasks to keep them at safe temperatures. Use insulated containers as directed by the manufacturer. Cook or reheat food thoroughly with core temperatures reaching at least 75°C for at least 30 seconds before packing it into an insulated container.
  • Cold foods such as sandwiches prepared with cold cuts and sushi rolls (raw ingredients not preferred) should be kept cold in a lunch box or bag. An insulated lunch box or a bag with frozen gel packs can be used to keep food cold and safe until lunchtime.
• Make sure all cutleries, containers, utensils and food bags are clean before use.
• Dispose of any leftover food in lunch boxes that have been kept at room temperature for too long as it is probably no longer safe for consumption.

Click here for more detailed advice for packing meals to school.