Ho! Ho! Uh-oh! New Zealand Food Safety deputy director-general Vincent Arbuckle busts some food safety myths to help you avoid giving your whānau and friends food poisoning over the festive season (and beyond).
1. You can reheat leftovers as many times as you like
One of the joys of the holiday season is having a mountain of leftovers. Reheating them once, to piping-hot temperature, shouldn’t be a problem (unless you’ve left them out too long before refrigerating or freezing). But every time you cool your food and reheat it, you give germs the opportunity to multiply, so doing this more than once raises the risk of foodborne illness. If you have a big batch of leftovers in the fridge, reheat only what you need, or divide it into meal-sized potions before freezing. Bin any unfinished reheated food. And, if your leftovers aren’t frozen, eat them within 2 days. While we’re at it, let’s bust the myth that leftovers are safe to eat if they look and smell okay. Although many nasties cause spoilage that will quicky make itself known in looks, texture, smell and (if you regrettably get that far) taste, there are many that are undetectable in the usual way. If in doubt, throw it out!
2. Hot leftovers should be left out to cool completely before refrigerating
Although it’s true that putting hot food in the fridge can drop its overall temperature slightly, it’s not as potentially detrimental to your health as waiting for your leftovers to cool completely. So, to decrease the risk of giving bacteria more time to grow on hot food, cool it for up to 30 minutes at room temperature (or wait till it’s stopped steaming), put it in a shallow dish (to help the food cool faster), cover, and pop it in the fridge, making sure there’s room for the air to circulate. Hot tip: most harmful bacteria can’t grow at low temperatures, so set your fridge to between 2°C and 5°C
3. Freezing food kills bacteria and viruses
Given how much frozen berries and Hepatitis A have been talked about over the past few months, this myth is fortunately losing a bit of traction. But to be clear, freezing doesn’t necessarily kill the germs that can contaminate food. The recent frozen berry recall is a good reminder that viruses, such as Hepatitis A, can survive freezing, freeze-drying, and heat of less than 85°C. Washing frozen berries also doesn’t get rid of the problem. When the berries start defrosting, the warmer conditions allow the bacteria to wake up and start multiplying. If you want to be sure your berries are safe to eat, boil them or cook them for at least a minute at more than 85°C. Then refreeze them in an ice tray to have handy as needed.
4. The best way to defrost food is to leave it out on the kitchen bench
Leaving your defrosting food on the bench is, in reality, the best way to give bacteria time to grow in a nice, warm environment. Bacteria thrive in temperatures between 5°C and 60°C, so, to decrease the likelihood of bacteria multiplying, and your food spoiling and making you sick, defrost it in the fridge, or in the microwave. Fun fact: bacteria are some of the fastest-reproducing organisms on Earth – they can double in number every 4 to 20 minutes!
5. It’s okay to eat shellfish that you have gathered raw, as long as it’s fresh
Kiwis love their seafood – and many people have traditionally gathered and eaten shellfish like mussels, kina, and pipi raw. But times have unfortunately changed. Vibrio is a type of bacteria naturally living in the sea, and some strains can cause gastroenteritis when consumed. Thanks in part to warmer sea temperatures, there’s more Vibrio around, so eating raw or undercooked shellfish, even fresh, can make you and your whānau very ill. Cases of Vibrio parahaemolyticus illness and hospitalisations have been increasing every year over summer. So, to help prevent illness, keep your gathered shellfish alive and cool, cook it thoroughly before eating, and keep raw shellfish away from other cooked or ready-to-eat food (so Vibrio can’t transfer to uncontaminated food).
6. You need to wash raw chicken before cooking it
Chicken in New Zealand has already been washed, so you don’t need to do it again. Although Campylobacter, Salmonella and other illness-causing bacteria live on raw chicken, it’s not a good idea to wash it again at home. Rinsing or washing it allows these bacteria to spread to other areas of your kitchen. If you’re worried about chicken juices, just pat it dry with a clean paper towel and then throw the paper towel away. While we’re on the topic of chicken, it’s also not okay to use the same chopping board, utensils, or plate for both your raw and cooked chicken. Anything that’s touched raw chicken needs to be washed in hot, soapy water before being used for any other food – and that includes your hands.
7. Eating foods after the ‘use by’ date is fine
We know times are tough and few can afford to throw away food, but if the ‘use by’ date on a packaged product in your fridge or pantry has come and gone, bin it. It is not safe to eat. In fact, it’s illegal to sell food past its ‘use by’ date. However, food should still be safe to eat after the ‘best before’ date, but it’s likely to have lost some quality. Stores can sell food beyond a ‘best before’ date, as long as it’s still fit for human consumption. Make sure to check the date on your food labels, so you can make a good call on whether to chow down or chuck out.
8. Plastic chopping boards are more hygienic than wooden ones
The key to a chopping board being hygienic is to thoroughly clean it after every use with hot, soapy water – particularly if you’ve been using it for raw meat, fish or shellfish. But, to bust the myth, research by food microbiology and toxicology expert Dr Dean O. Cliver showed wooden chopping boards retain less bacteria than plastic boards, particularly if the plastic has been damaged by knives, providing convenient spots for bacteria to hide before transferring onto other food. He found that wood, because it’s porous, absorbs the bacteria – and although the bacteria doesn’t die immediately, neither does it return to the surface of the board. So wood is the better option. As for glass and stainless-steel cutting boards, they’re not porous like wood and don’t scratch easily like plastic, so keep them clean, and happy chopping!
9. It’s okay to eat a little bit of raw cookie dough or cake batter
Unfortunately, it’s not okay. Raw flour – and raw whatever-else-you’ve-popped-in-your-dough – can carry illness-inducing bacteria. Baking will kill that bacteria. Although there are clear food standards and food safety guidelines in New Zealand, raw flour can be contaminated with Salmonella, so, remember the rhyme: ‘Just a lick can make you sick!’
10. You don’t need to wash bagged greens or salads
Any bagged lettuce, salad, or other manner of greens you buy, still need to be washed first before using. Under running water in a clean colander in the sink will do. This will reduce any food safety risks due to bacteria or chemical residues.
11. If you drop food on the floor and pick it up within 5 seconds, it’s safe to eat
Sorry, the ‘5-second rule’ is a myth. Whether it’s 1 second or 10, all bacteria and viruses need to get onto your food – and into your gut – is any contact at all. Although the moisture and stickiness of the food will affect the number of germs that will attach to the food, to be safe, if you’ve dropped it on the way to your mouth, best to bin it – and wash your hands. If you’ve dropped it during food preparation – and it can be salvaged (we’re not talking spilt milk and broken eggs) – and if you really can’t bear to throw it away, rinse it and make sure it’s cooked thoroughly to kill unwanted nasties.
12. Mouldy food is okay to eat, as long as I cut off the mouldy bit
That spot of mould you scrape of your bread, or the one you cut off your cheese, is the tip of the iceberg. Mould have spores and roots going into the food, which you often can’t see. They can also produce toxic chemicals called mycotoxins that can make you really ill. Not all moulds are bad – some make life-saving medicine (penicillin) and delicious cheeses. Fun fact: the mould used in the production of camembert and brie is named Penicillium camemberti, after the cheese first made in the late 18th century in Camembert, France.