Food safety in the Christchurch earthquake

Thursday 24 February 2011, 7:56AM



MAF (Food Safety) has issued this advice to protect people from foodborne illnesses in the wake of Tuesday's earthquake.

For further emergency information go to (External website)

During an emergency: minimise food and water spoilage

During an emergency normal household appliances such as fridges and ovens may break down or lack power, our food could spoil faster and our water supply could become contaminated. To avoid this happening follow the steps below:

• eat perishable foods, for example bread and meat first, as they spoil faster than non-perishable food

• eat canned foods last

• minimise food spoilage by opening the fridge or freezer only when you need to take food out

• do not eat vegetables or fruits that have been lying in flood water

• cover all food with plastic wrap or store in waterproof containers

• leave bottles, drink cans and water containers in the fridge (if it’s working) to keep things cold

• throw out rotting or tainted food before it spoils other food.

During an emergency: focus on hygiene Maintaining hygiene around food preparation and cooking requires more thought than normal.

• always wash and dry your hands before preparing food – if water is in short supply keep some in a bowl with disinfectant

• ensure all utensils are clean before use

• cook food thoroughly

• cover all food with plastic wrap or store in waterproof containers

• keep a supply of fly spray

• rubbish containing food scraps must be protected from flies and rats by wrapping or putting in a sealed container.

During an emergency: use safe cooking and washing water

The following household facilities can be used to cook, wash dishes, and wash your hands:

• hot water cylinder

• toilet cistern – as long as no chemical toilet cleaner is present

• bottled water

• spa/swimming pool – can use to wash yourself and your family.

Boil or purify water before using it in food preparation, and to avoid cross-contamination of food. Once boiled, cover and store in a clean container and place in the fridge (if it’s working) or in some other cool place. Re-boil the water if it is not used within 24 hours.

If you do not have power to boil water then purifying tablets or bleach can be added to ensure its safety. Add five drops of household bleach per litre of water and leave for 30 minutes.

After an emergency: ensure food is safe

Knowing what is safe to eat during the ‘clean-up’ phase after an emergency can become a guessing game. Understand what may or may not be safe to eat:

• any food that retains ice crystals and where the packaging has not been damaged or opened can be safely refrozen

• foods that have been defrosted can still be used if they have just recently defrosted and can be kept cold, ie the fridge is working again

• defrosted food cannot be refrozen

• inspect the food – does it smell or appear different? (Has the colour changed and does it have a slimy texture?), if so it is probably unsafe to eat

• do not use any tinned food that has been damaged (for example if the can has split seams or has been punctured).

You should always be prepared for a disaster. If you follow the guidelines above, they may help prevent you or your family from becoming ill.

Food safety is just one step in staying safe during and after an emergency. To find out more visit the Civil Defence website:

Before the next disaster strikes: prepare a survival kit

There are many things you can do to minimise the impact on your health before disaster strikes. Put together an emergency food survival kit. Do it now and make sure you include the following items to last at least three days:

• canned and/or dried food – luncheon meat, ham, fish, fruits, vegetables, cereals, tea, coffee, powdered soup, salt, sugar, sweets, biscuits

• a can opener

• a primus/portable gas cooker or barbeque to cook on

• eating equipment – utensils, knives, pots, cups, plates, bowls, matches, lighters

• bottled water – 3 litres per person per day, or 6 to 8 large plastic soft-drink bottles of water per person per day

• bottled water – 1 litre for washing food and cooking each meal, washing dishes and washing yourself

• milk powder or UHT milk.

Check and renew food and water every year, taking into account medical or dietary conditions in your family. If you have babies or children, make sure they have enough suitable food.

If you live in a flood-prone area, keep your food survival kit above the likely reach of flood water.

As you get your business up and running again it's vital some extra steps are taken to ensure food is safe for your customers.

What you do next will depend on the amount of damage to your premises and equipment, the availability and amount of drinking water supply you need, condition of food in stock and the type of food you want to sell. The following points and the 'Restarting a Food Business checklist' provide a quick summary of the most important things to consider as a café, restaurant or food retailer reopening for business.

1. Are premises structurally sound for preparing or handling food?

Once the building has formally been declared as safe you will need to make sure any damage to food areas does not stop you from operating hygienically. Is there a chance that food will become contaminated, such as from leaking pipes, sewage, or damaged ceiling or wall claddings falling onto food?

Make sure the services you need for power, water supply and drainage haven't been damaged or weakened in the premises.

2. Are toilets and personnel hygiene facilities working?

Make sure toilets for staff and customers are in working order. If a 'boil water' notice is in effect, staff should wash hands using cooled boiled water, or water treated with bleach/chlorine (5 drops of bleach to one litre of water); then use a hand sanitiser. Hand wipes and hand sanitisers may be sufficient for customer hygiene.

3. Can the premises be thoroughly cleaned before use?

Areas used for food preparation and serving will need to be thoroughly cleaned, and food preparation surfaces and utensils sanitised before use to ensure there is no risk to food safety.

4. Is the water safe to use?

If a 'boil water' notice is in effect, it is recommended that you use a use a supply of bottled drinking water if you need to use water as an ingredient in food while the notice is in place.

Turn off ice machines until the 'boil water' notice has been lifted.

Most coffee machines only heat water to 80 - 85° C, so these machines need to be supplied with pre-boiled water. Plumbed-in machines should not be used.

Remember to only use cooled boiled water, or water treated with bleach/chlorine (5 drops of bleach to one litre of water) to wash hands when preparing food. Use a sanitiser after washing hands, especially if water is scarce.

Identify the best way to boil or chlorinate the water needed and someone responsible for maintaining the supply.

Using disposable gloves might help, but remember to change them regularly and wash your hands in clean water when you do so.

When the 'boil water' notice has been lifted, run taps to check the water before you use it. If you notice anything unusual with the colour or cloudiness or smell, contact your water supplier for advice. Don't use the water until your supplier has confirmed that it is OK. Further information about water in food businesses can be found at:

5. Is food still safe to use?

Check how long fridges, chillers and freezers have been without power as food safety may have been affected. As a 'rule of thumb':

  • If power to fridges and chillers was off for less than 24 hours, and chillers were not opened during the power cut (or only opened briefly to add bags of ice) contents must be checked but should be OK.
  • If power was off for more than 24 hours, or chillers were opened (eg not to add bags of ice) readily perishable food should be discarded.
  • In any case, food beyond its ‘Use-by’ date code must be thrown out.

Readily perishable foods are those that need to be kept below 4°C.  These are foods containing meat, fish, dairy products; plus prepared salads, sandwiches, cooked rice and pasta and processed foods containing eggs, beans, nuts or other protein-rich foods.  Any microbes on these foods grow when the temperature of the food increases.

  • Perishable foods in the chiller, for example fruit and hard cheeses, may still be safe to use if they are not showing obvious signs of spoilage.
  • If a freezer was full, power was off for less than 4 days and the freezer was not opened during the power cut and there is no evidence of thawing, contents should be OK to use.
  • If power was off for more than 4 days, or the freezer was opened during the power cut, or the freezer was not full or there is any evidence that contents have completely thawed, or have thawed then refrozen, then DO NOT USE THE FOOD – throw it out.  And don’t feed it to your pets.
  • Partially thawed food in the freezer should be completely defrosted and used immediately.

Food still frozen with ice crystals throughout can continue to be kept frozen if you are sure it did not thaw out and then re-freeze when the power came back on. Frozen food that has defrosted and was refrozen when the power was restored should not be used. This will not always be obvious, but important signs of defrosting and refreezing will be misshapen products, or drip from packaging that has become frozen, or packages stuck together, or the pooling of frozen fluids in the bottom of sealed packages. 

6. Is refrigeration working?

Make sure chillers, freezers, display cabinets and other equipment has not been damaged and will work as intended.

7. Food on the menu

Think about providing food that needs little preparation, reaches high cooking temperatures and keeps handling to a minimum.

8. Sourcing new supplies

If you are restocking from local suppliers ensure perishable or frozen foods were not affected by power outages. So check that your supplier has taken the steps indicated in 5. above.

9. Do your staff know what to do?

It is important everyone knows what they must do to produce safe food during an emergency, particularly if there is a disrupted clean water supply. It is vital hands and food preparation surfaces are kept clean. Mark different pots and pans being used to boil or cool water so people know which to use. If in any doubt about what you should do, contact the Environmental Health Officer at your local council.