A rumor recently made the rounds in our newsroom: Eating stale rice or pasta can be deadly. Since we sometimes eat our Thai lunch from the day before, many of us were a bit shocked.
So we googled and found that there are actually documented cases, for example in Belgium, of people dying of food poisoning after eating rice or pasta. In a 2005 case, a young girl died after the family ate a pasta salad from the previous day’s picnic.
In a second case, in 2011, a young student died of poisoning after consuming reheated pasta with tomato sauce. Research then showed that the culprit is the spore-forming bacteria Bacillus cereus. It can produce toxins that attack the liver after eating the food – and this can be deadly.
But how common are such cases? And has that already happened in Switzerland? How can we prevent food poisoning? We wanted to know more about it and asked the man who deals with it every day: Martin Loessner, Professor of Food Microbiology at ETH Zurich.
Mr Loessner, have you heard of the cases described above?
Yes, I am very familiar with these cases. I teach at the university and deal with these two cases, which have resulted in so-called case studies, over and over again.
How dangerous is that now? Bacillus cereus?
In the beginning: Bacillus cereus It’s not called that by accident. cereus comes from the word grains – it is found in grain products such as pasta or rice. The reason is that this Bacillus distributed over earth and dust.
As for the danger that ensues, you have to make certain clear distinctions.
Which?
These bacteria are among the few that can produce two different types of so-called toxins. With the different types come very different syndromes.
And which one would that be?
One type causes diarrhea. Here, vegetative cells and/or spores (bacteria in the early stages) of Bacillus cereus taken through food. The toxin then forms later in the small intestine. In addition to diarrhea, these toxins can in rare cases cause damage to intestinal cells. But the other type is actually much more dangerous.
And which one would that be?
This type does not lead to diarrhea, but to vomiting. The toxin responsible for this is called cereulide. It is formed in the food itself and then absorbed.
And why is that so dangerous?
Once ingested, cereulide passes through the stomach and small intestine into the bloodstream and eventually to the liver. There it then leads to a very rapid and fulminant death of liver cells. After all, that is the actual cause of death, as in the cases you mentioned.
What if the food is preheated?
The problem is that this toxin is extremely heat resistant. It cannot be turned off by heating the food. However, other bacteria that Bacillus cereus compete are deactivated during the heating process. The latter can therefore quite easily “celebrate a big party”. This means that warming actually promotes their growth.
What exactly needs to be done for fatalities to occur?
It’s always the same: storing food that has been cooked for too long at too high temperatures. In the case of the sick family, for example, it turned out that the refrigerator was much too warm – namely 14 degrees! This is of course deadly.
What temperatures are okay?
If the fridge is cool enough, you can keep pasta or rice for three to four days without a problem, but with a week you have to be a little careful. That would certainly be the maximum. But: The refrigerator should never be set warmer than six degrees.
Oh okay Then the energy saving tips mentioned by some are not so smart – raise the temperature in the fridges a bit?
No, that would be a big mistake! Under no circumstances should you do that. At this end you can just Not save.
Good to know. And what was the problem in the other case?
The student left his pasta outside on the weekend, not in the fridge. When he came back from a walk, he ate them – not a good idea.
Understood. Short question here: Very few people put the pasta back in the fridge right after cooking. Can something happen there too – if I leave the leftovers in the pan for five hours, for example?
No, no, that’s not a problem. We’re talking longer periods of time – that should be at least one or two days when the food is way too hot. However, you should never generalize.
What do you mean?
We are now only talking about this bacteria
(Bacillus cereus) and already cooked food. Other foods, such as meat, should never be kept warm for longer. But these are other microorganisms that play a role.
OKAY. Back to the deaths: Do you also know deaths in Switzerland?
Yes and no. I’m sure I know of cases from Switzerland or neighboring countries. But they are not as well documented as the cases from Belgium.
What scale are we talking about here?
You can’t say that, because that Bacillus cereus is not a notifiable disease. The BAG therefore does not keep statistics on this. I estimate that there are at least a few hundred to a thousand cases a year in which someone comes into contact with this bacterium. Then there is diarrhea or vomiting. In these cases one simply speaks of food poisoning – although it is actually true here.
Otherwise not?
In most cases not, no. It is usually a foodinfection – the ingestion of bacteria, for example salmonella or E coli-Bacteria. These cause an infection and not poisoning. Bee Bacillus cereus it’s the toxins that pose a threat.
Back to business in Switzerland: do you know of one that ended fatally?
No, I don’t know about that. They certainly are, but they are not documented.
Why not?
Because, as mentioned, publication is not mandatory. This means that in the event of death, it is certainly noted internally after the investigations. But not published. It is rare for such cases as discussed above to be discussed publicly as case studies.
Infectious diseases, on the other hand, are reported. But very little here. On the contrary, poisonings do not have to be reported.
Are they hard to spot?
Yes – the symptoms are similar to many other diseases. But it is also crucial that poisoning by Bacillus cereus are generally very rare. This in comparison with other food diseases, where sometimes real epidemics prevail. These then develop on other foods, such as meat or other protein foods.
Certain individuals are actually more at risk than others, with potentially fatal poisoning Bacillus cereus suffering?
No, it really depends on the dose alone. The higher this is, the more dangerous. However, for children it can be more threatening because their liver is simply smaller and therefore they have a lower tolerance.
no Unfortunately one cannot help such a poisoned liver. It’s just too fast.
Finally, can the toxins be identified in any form?
A good question. In the vast majority of cases, laymen can’t, but experts can.
How is that possible?
These bacteria make very special metabolic products that you can smell. But they are very nice notes. It smells a bit like something fermented, also a bit like yeast. Sometimes you see it too.
How exactly?
A whitish, greasy layer is then formed
above the food, sometimes even on the bowl, on the edge of the bowl or pan. By the way, you can do this experiment.
OKAY…
Then you can cook rice, drain, leave the lid on and leave for five days – but don’t take the lid off! And then after five days you can see how Bacillus cereus looks like.
ohh So you can assume that the bacteria will show up anyway?
Yes – it is always there. But of course not everyone can do that Bacillus cereus produce these toxins, that’s important to know. Only about ten percent of Bacillus cereusStrains can produce this cereulide, the dangerous toxin. Not everyone else.
Source: Blick
I am Ross William, a passionate and experienced news writer with more than four years of experience in the writing industry. I have been working as an author for 24 Instant News Reporters covering the Trending section. With a keen eye for detail, I am able to find stories that capture people’s interest and help them stay informed.
