When to rescue food and when to chuck it out, according to a nutritionist

by Emma Beckett, The Conversation

edited by Lisa Lock, reviewed by Andrew Zinin

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Got some brown bananas on the counter, or soggy salad in the fridge? If so, you're not alone. Research shows on average, Australian households waste about 30% of the food we buy—or 2.5 million tons each year.

But in a cost of living crisis, where everything from fuel to groceries is getting more expensive, wasting food feels especially painful.

These economic pressures mean more Australians are using food relief services. Many are also buying fewer fresh foods and are taking more risks around food safety.

But with a bit of knowledge and creativity, you can salvage certain foods without risking your health.

Don't risk it

It's worth noting, you won't be able to rescue every bit of food. That's because they may have become unsafe to eat.

Here are four key signs to look out for.

1. visible mold
2. slime
3. leaking liquid
4. strong or sour smells.

If you have food that has one or more of these signs, it's best to bin it. That way you can avoid food poisoning, which can cause stomach pain, nausea, vomiting and diarrhea.

But other characteristics, such as wrinkles, browning and dryness, are often just signs of age, not harmful spoilage.

Fruits

Brown or black bananas may look unappealing, but they are perfectly safe to use in banana bread, pancakes or smoothies. But it's best to keep any old bananas away from your fresh ones because darker bananas produce ethylene gas, which makes other fruit ripen faster.

Old apples may look wrinkly, because they lose water as they sit. But these apples are ideal for stewing, baking or grating.

Citrus skins, such as those from lemons or oranges, go tough and dry with age. However, you can still use the zest in baked goods and marmalade, and the flesh in drinks, dressings and marinades.

If you notice any mold on larger, firm fruits, it's generally safe to cut it off. Just make sure you chop off the moldy section with a large margin of at least a few centimeters. But if you find mold on soft or small fruit, such as berries, it's best to throw it out.

Vegetables

Floppy or shriveled veggies have lost moisture, but are not necessarily spoiled. You can roast, mash or puree them, adding them into everything from soups to curries. You can also use an ice-water soak to revive leafy greens such as spinach or kale. This involves separating the leaves and soaking them in cold water for at least 30 minutes to re-hydrate them.

For firm vegetables such as potatoes, carrots and pumpkin, any damaged or bruised areas can often be cut off. With potatoes, however, look out for any extensive greening or sprouting, as these contain natural toxins that are harmful if eaten in large amounts.

You may notice a fluffy white fuzz developing on mushrooms. This usually is not mold but mycelium, which is part of the mushrooms' root system. Mold can grow on mushrooms but often appears in isolated, brightly colored clusters that look blue, green, gray or yellow.

Grains

It's best to discard any moldy bread. This is because mold spreads more easily in porous foods, such as bread and cakes. But you can save stale, mold-free bread by toasting or turning it into croutons or breadcrumbs. And storing bread in dry environments—such as a bread box, cloth or paper bag—means mold won't grow as quickly.

You can use leftover cooked rice or pasta in stir-fries or pasta bakes within a couple of days. But make sure to promptly and properly store it in the fridge and reheat it fully, meaning to piping hot or at least 60°C. And if heating in the microwave, make sure to stir so the food heats evenly. But, always discard any leftovers that have sat at room temperature for two hours or more, as they may contain bacteria that you can't simply remove by reheating.

Dairy

We often consume milk and yogurt straight from the fridge, without a cooking or reheating step to kill bacteria. So it's safest to chuck dairy products that are past their use-by date. And to prevent premature spoilage, only use clean utensils to serve dairy products and promptly return them to the fridge.

If you're a fan of soft cheeses but notice any mold, throw the whole block or wheel away. This is because the roots of mold can penetrate deep into the cheese. Hard cheeses such as parmesan aren't as susceptible to mold, so you can often cut off any moldy bits with a generous margin. Proper storage—for example wrapping it in wax or baking paper and placing it in a container—can help cheese last longer.

There are many ways to rescue food that's past its prime, but not spoiled. By following some simple food safety rules, and thinking outside the box, you can both reduce waste and save money.

Key medical concepts

Foodborne IllnessBacteriaDairy Products

Clinical categories

Nutrition & Healthy eatingPreventive medicineHealthy livingCommon illnesses & Prevention Provided by The Conversation Who's behind this story?

Lisa Lock

BA art history, MA material culture. Former museum editor, paramedic, and transplant coordinator. Editing for Science X since 2021. Full profile →

Andrew Zinin

Master's in physics with research experience. Long-time science news enthusiast. Plays key role in Science X's editorial success. Full profile →

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