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Food Safety Focus (207th Issue, October 2023) – Article 2

Securing Food Safety During Adverse Weather and Extreme Conditions

Reported by Mr. Kenneth YIP, Scientific Officer,
Risk Communication Section, Centre for Food Safety

Hong Kong often experiences adverse weather and extreme conditions due to tropical cyclones and storm surges particularly in summer, which could result in flooding and power outages. While the public may stock up food in preparation of these emergencies, flooding and power outage could expose food to improper storage conditions, causing spoilage and contamination. This article will discuss the strategy to prepare for food storage, and will highlight steps to secure food safety when facing flooding and power outage.

Plan and Store Suitable Amount of Food Wisely

Some may consider buying and storing food more than required before the approaching adverse weather and extreme conditions. It is essential to store the food properly to avoid spoilage and it is preferable to purchase only  the quantity needed. Before purchase, keep a running list of meals and their ingredients and reserve sufficient storage capacity. Do not buy food that is near or past its expiry date

After purchase, food should be kept according to storage instructions like keeping them refrigerated at ≤4°C or frozen at ≤-18°C. Cooked and perishable foods like fresh meat and poultry, aquatic products and milk should be refrigerated within 2 hours. To prevent contact between raw food and ready-to-eat or cooked food, they should be stored separately in covered or sealed containers. Do not overload the refrigerator to maintain proper cold air circulation. For non-perishable food items, they should be kept in a cool and dry place.

Salvage Food after Floods – Safe or Not?

All perishable food that has not been refrigerated or frozen properly due to power outages should be discarded. During flooding, food may become submerged in floodwater. Floodwater may contain pathogens and can contaminate food. It is important not to consume any food that has been submerged in floodwater and has not been packaged in waterproof containers. All non-prepackaged foods and those not in waterproof packaging that have come into contact with floodwater should be discarded. Only foods packed commercially in metal cans with double-seamed lids and retort pouches are regarded as waterproof and may be salvageable after they are thoroughly cleaned, sanitised and labelled. Any food with an unusual odour, colour or texture should be thrown away.

Figure 1: Examples of food items eligible and not eligible for food recovery

How to Wash and Disinfect Utensils after Flooding?

For those containers and dishware made of waterproof materials that may come in contact with food, they can be reused after thorough washing and sanitising. These include metal pans and ceramic dishes. They can be washed with soap and water and then rinsed accordingly. Sanitise the cleaned utensils by boiling in clean water or immersing them in 1:99 diluted household liquid bleach for 15 minutes, and then allow them to air dry. Wooden and plastic utensils like cutting boards should be discarded if they contacted with flood water as they cannot be safely cleaned.

Keeping Food Safe in Case of Power Outage

Most refrigerators and freezers do not have backup power supply. They will stop circulating cold air when the electricity is lost, which could expose food to unsafe temperatures. Keeping frozen gel packs, ice cubes and dry ice in refrigerators before power outage can help to store food at safe temperature for a longer period of time. It is advisable to have a thermometer in the refrigerator to indicate the temperature to help determine if the stored foods are still safe to consume afterwards. If no thermometer is available, we can still keep track of the downtime to help us to determine if the stored foods are still be safe. Keeping refrigerator and freezer doors closed can maintain cold temperature. The food stored in chillers will stay safe for 2 to 4 hours if doors have been unopened, and food can be kept for 24 hours and 48 hours in half-full and full freezers respectively.

Once the power returns, check the temperature of refrigerators and freezers and investigate if perishable foods like fresh meat and poultry are exposed in the Temperature Danger Zone between 4°C and 60°C. For high-risk food stored within the Temperature Danger Zone, follow the 2-hour/4-hour rule. Some frozen foods may still contain ice crystals and could be safe to refreeze or cook. However, ice-cream should be discarded even if it feels cold as if refrigerated. Never taste foods to determine whether they are safe to eat, as they might not give off an abnormal taste or odour even if they are spoiled.

Figure 2: Food safety tips before adverse weather and extreme conditions, after flooding and after electric outage

Securing food safety during adverse weather and extreme conditions is essential. In addition to getting ready for the food reserve, the trade and the public should be set to handle flooding and power outage. Food business operators should ensure that food is fit for human consumption and discard spoiled food. The public should be vigilant in identifying food items eligible for recovery and salvage them properly before consumption.