Which foods are no longer eaten?

You really shouldn't eat these tainted foods anymore

Food waste: food waste or spoiled?
We'll show you whether you can still trust the milk, the salad and the basmati rice from the day before yesterday.
Rotten salad, smelly yogurt, moldy bread: what can you still eat and what not?

Is it still edible or can it go away? We ask ourselves this question all the time - and often throw food away. Around a million tons of food end up in the garbage every year in Switzerland. Some of them would still be edible, some not. If there are any signs, however, you should definitely stay away from the edibles.

Moldy bread

Sometimes you can see it from a distance: the crème fraîche or the orange is covered in mold. Another time you take a closer look at your groceries and suddenly ask yourself: Does the strawberry look suspiciously gray at the bottom of the pack or the edge of the bread?

Then the best thing to do is to keep your hands off it. Because when molds have settled somewhere and start to grow, they also produce hundreds of toxic substances, the so-called mycotoxins. And while a moldy slice of bread that we once ate rarely becomes really dangerous, regular consumption can even promote cancer. The following therefore tends to apply: what is - unintentionally - moldy belongs in the bin. Because even if the spores only show up in a small area, a moldy coating on a strawberry can indicate that the spores have already passed through the other berries. Even if there is mold on bread, the loaf belongs in the bin. You can be a little less strict with jams with a sugar content of at least 50 percent. Spoon off the affected areas generously. However, this does not apply in reverse: Please never make jam from moldy fruits! The toxins are heat-resistant.

Smelly yogurt

Yoghurt is a good example of the fact that many things last for days to weeks after the printed best-before date. You can then easily tell whether it is still good by the fact that it looks, smells and tastes normal. Because when a food goes bad, microbes are mostly involved and start to eat it. In doing so, they excrete a large number of substances and gases, some of which are not well tolerated. Most of the time, these smell unusual to putrid. When we turn to the food in question, volatile substances are transported with the air we breathe to the olfactory cells, which in turn send a signal to the brain. We perceive several thousand different smells - and our alarm bells ring. If we have eaten a spoonful of yoghurt despite the warning signal, this is still not threatening - the high concentration of undesirable microbes could, however, trigger stomach ache and diarrhea.

Putrid salad

You think my pre-cut salad from the bag is not moldy yet. The interfaces are brown, but shouldn't be a problem. But wait: It is precisely these interfaces between fruits, vegetables or lettuce that can easily be attacked by microbes. Certain bacteria, molds and yeasts destroy the cell membranes, eat the inside of the cells and convert it into unwanted waste. Therefore, pre-cut salads packed in plastic are particularly problematic. Because only microbes can hold onto the raw lettuce particularly well. And the interfaces make prepared salads particularly vulnerable. You should only eat it if you haven't kept it in the refrigerator for more than a few hours after buying it and now wash it again - at least that's what the German Federal Center for Nutrition recommends. So you better keep your fingers off the lettuce of the day before yesterday, from whose plastic bag you now have a slightly putrid smell.

Slimy milk

And what about the rest of the milk that has been there for a while? You think to yourself: Can I bake a pancake with it or at least pour it safely into the coffee? Take a look at it. A strange smell indicates that too many bacteria were at work here. It doesn't have to be a bad thing. Lactic acid bacteria in raw milk have been used for thousands of years to make acidified products such as yoghurt, crème fraîche or buttermilk and thus make them more durable. This happens because certain lactic acid bacteria convert the lactose into acid. The sour smell and taste of the "curdled milk" created in this way takes some getting used to, and it flakes out quickly in warm drinks. But you can always use the sour milk for baking and cooking. So nothing stands in the way of the pancake.

However, you should no longer use the milk if it has developed a very sour or otherwise unpleasant aroma. Some microbes such as Bacillus cereus, Clostridium botulinum or Clostridium perfringens not only produce bad smells and tastes by breaking down certain enzymes and producing acids and gases (such as CO2 and H2), but they also produce toxins that can be poisoned by dairy products being able to lead. As a comparison for your nose: In one study, the aroma of spoiled milk reminded the test subjects, for example, of the smell of babies' vomit, of rotten hamburger meat or of small animal practices.

But even if milk is old without smelling, it could be unpleasant. And that applies to the opened pack of UHT milk. This milk, which is germ-reduced by heating to up to 150 degrees, can turn bad once it is opened. Microbes such as Pseudomonas enter opened packages through the air. There they break down proteins and fats, which leads to a bitter taste without necessarily producing a special smell. That is why you should not only check older UHT milk with your nose but also with your eyes: Pseudomonads cause it to become slimy and pull threads.

Infested rice

And how about some warmed-up basmati rice? After all, you only cooked it yesterday, and it flashes at you as white as innocence, even if you left it in the kitchen for half the night. A familiar basmati smell also flows towards you.

The case is clear - one might think. However, the bacterium Bacillus Cereus often lurks on rice, pasta and cereals, whose spores can withstand long waiting times as well as high temperatures. If rice is then cooked and slowly cooled, B. Cereus becomes active. At temperatures between 5 and 65 degrees Celsius, it can produce around 19 different toxins, which in rare cases can even lead to death, but mostly the toxins cause vomiting, diarrhea and abdominal pain. The nasty thing about it: You can neither smell nor taste an excessive infestation of Bacillus Cereus. Anything that has remained at room temperature for more than an hour after cooling should therefore not be eaten as a precaution.

You see: old groceries are a difficult thing. Instead of piling up your food in the refrigerator and letting it spoil, there is another solution: Plan your meals, shop carefully - and eat the delicacies as quickly as possible.

higgs will help you

Here we make the little annoyances of everyday life disappear for you. We're starting with a series on the chemistry of cooking - because those who understand processes cook better and are less frustrated when things don't work out. But that's just the beginning. Little by little we will penetrate all areas of life, be it sport, after work or love. Are there everyday questions that we can explain to you? Write us your ideas and inputs at [email protected]
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