Cathy Moir: Five food myths busted

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Dangers lurk in food, but the news isn’t all bad.
Bacteria, yeasts and moulds are the usual culprits for making food smell off and these may not make you sick. Photo / Getty Images
Bacteria, yeasts and moulds are the usual culprits for making food smell off and these may not make you sick. Photo / Getty Images

This time of year, most fridges are stocked with food and drinks. As the weather warms up, so does the environment for micro-organisms in food, potentially allowing them to multiply faster to hazardous levels.

So put the drinks on ice and keep the fridge for food. But what are some of those food safety myths that aren't true?

1. If you've defrosted meat or chicken you can't refreeze it

It is fine to refreeze meat or chicken or any frozen food as long as it was defrosted in a fridge running at 5C or below.

Quality may be lost by refreezing as the cells break down and the food can become slightly watery.

Another option is to cook the defrosted food then divide into small portions and refreeze once it has stopped steaming.

Steam in a closed container leads to condensation, which can result in pools of water forming.

This, combined with the nutrients in the food, creates the perfect environment for microbial growth. Wait about 30 minutes before refrigerating or freezing hot food.

Plan ahead so food can be defrosted in the fridge. If left on the bench, the external surface could be at room temperature and micro-organisms could be growing rapidly while the centre of the piece is still frozen.

2. Wash meat before you prepare and/or cook it

It is not a good idea to wash meats and poultry when preparing for cooking. Splashing water that might contain potentially hazardous bacteria around the kitchen can create more of a hazard if those bacteria are splashed on ready-to-eat foods or preparation surfaces.

Wash fruits and vegetables before preparing and serving, especially if they're grown near or in the ground as they may carry dirt and micro-organisms.

This applies particularly to foods that will be prepared and eaten without further cooking. Eating foods raw that traditionally have been eaten cooked or otherwise processed to kill pathogenic micro-organisms (potentially deadly to humans) might increase the risk of food poisoning.

Fruit, salad, vegetables and other ready-to-eat foods should be prepared away from raw meat, chicken, seafood and other foods that need cooking.

3. Hot food should cool completely before putting it in the fridge

It's not okay to leave perishable food out for an extended time or overnight before putting it in the fridge.

Micro-organisms can grow rapidly in food at 5C-60C. Temperature control is the simplest and most effective way of controlling the growth of bacteria.

Perishable food should spend as little time as possible in the 5C-60C danger zone. If food is left in the danger zone, be aware it is potentially unsafe to eat.

Hot leftovers, and any other leftovers for that matter, should go into the fridge once they have stopped steaming, within about 30 minutes.

Large portions of hot food will cool faster if broken down into smaller amounts in shallow containers. Hot food such as stews or soup in a bulky container, say a two-litre mixing bowl (versus a shallow tray), in the fridge can take nearly 24 hours to cool to the safety of less than 5C.

4. If it smells okay, then it's okay to eat

This is definitely not always true. Bacteria, yeasts and moulds are the usual culprits for making food smell off or go slimy and these may not make you sick, but it is always advisable not to consume spoiled food.

Pathogenic bacteria can grow in food and not cause any obvious changes to the food, so inhibit pathogen growth by refrigerating food.

5. Oil preserves food so it can be left at room temperature

Adding oil will not necessarily kill bugs. The opposite is true for many products in oil if anaerobic micro-organisms, such as Clostridium botulinum (botulism), are present. Lack of oxygen provides perfect conditions for their growth.

Outbreaks of botulism arising from consumption of vegetables in oil " including garlic, olives, mushrooms, beans and hot peppers " have mostly been attributed to products not being properly prepared.

In 1991, Australian regulations stipulated that vegetables in oil can be safely made if the pH is less than 4.6. Foods with a pH below 4.6 do not in general support the growth of food-poisoning bacteria, including botulism.

Cathy Moir is a senior food microbiologist and vice president of the not-for-profit Food Safety Information Council

- Herald on Sunday

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