These are the places where a microbiologist would never eat

2023-10-04 14:58:51

Every year, around 2.4 million people in the UK get food poisoning, mostly from viral or bacterial contamination. Most people recover within a few days without treatment, but not everyone is that lucky.

As a microbiologist, I am probably more aware than most of the risk of food infections. These are some of the things I pay attention to.

Eating outdoors

I rarely eat at picnics or barbecues, as the risk of food poisoning increases when food is consumed outdoors.

Keeping your hands clean when handling food is key to not getting sick, but how often do we find hot running water and soap in a park or on a beach? We can use alcohol hand gel (it is better than nothing), but it does not eliminate all germs.

Additionally, food tends to attract a variety of flying and crawling bugs, such as flies, wasps, and ants. All of them can transfer germs like E. coli, Salmonella and Listeria to what we put in our mouths.

Keeping perishable foods cold and covered is essential, as germs can double in number if food is allowed to warm at 30℃ for more than a few hours. For barbecues, meat must be cooked thoroughly, and a meat thermometer is a good investment to avoid food poisoning. It is not advisable to eat meat if its internal temperature is below 70℃.

Buffets

Knowing under what conditions food-related bacteria prefer to grow, I am keenly aware of the limited microbiological safety of hot and cold buffet displays.

Inside, food can be exposed to contamination from insects, dust and, above all, people. Buffet visitors spread germs when they touch the food, or when they sneeze and cough near the displays. On the other hand, contamination by insects – such as flies or wasps – that land on uncovered food must be taken into account. Germs can also be deposited from the air, which is rich in bacteria, fungi and viruses.

Food poisoning is, therefore, an inevitable risk when we have lunch or dinner at a buffet.

I always check the clock when I’m in them, as there is a two-hour restoration rule: perishable foods are no longer safe to eat within two hours if they are not kept covered and refrigerated. The problem is that buffets are often prepared before diners arrive, making it difficult to know how long the appetizingly arranged platters of meat, seafood, salads, desserts, and fruits and vegetables have been there.

At hot buffets, such as those served at hotel breakfasts, I always avoid warm food, since bacteria that cause food poisoning can grow rapidly when food is kept below 60℃. Hot foods should be served just like that, hot. That is, at a temperature of at least 60℃.

If I have any doubts about the safety of the food on offer, I reluctantly eat freshly toasted bread and individually packaged jam for breakfast.

Oysters no, thanks

There are some foods I never eat. Raw seafood, such as oysters, is one of them. This is because oysters are filter feeders and can concentrate germs, such as Vibrio and norovirus, in their tissues.

An oyster contaminated with Vibrio doesn’t look, smell or taste any different., but it can make us very sick. The U.S. Centers for Disease Control and Prevention estimates that about 80,000 people contract Vibrio infections from raw oysters. And one hundred people die from vibriosis every year in the US alone.

It is also possible to get food poisoning from eating any raw seafood (clams, mussels, whelks, cockles). I only eat seafood that is well cooked, because heat effectively kills harmful germs.

Germs in bagged salads

I never eat bagged salads, largely because one of my areas of research is the safety of fresh salads. It has been found that bagged lettuce can contain food poisoning germs such as E. coli, Salmonella and Listeria.

My research group has found that these pathogens grow more than a thousand times better when given the juice of salad leaves, even if the bag of salad is refrigerated. What is really worrying is that the aforementioned germs use salad juices to become more virulent and, therefore, more effective in causing an infection.

For salad lovers alarmed by this information, most bagged salads They are safe if kept refrigerated, wash well before use –yes, even ready-to-eat salad needs to be washed– and consumed as soon as possible after purchasing.

Cooked rice is never reheated

As far as cooking practices go, I have an exhaustive list of dos and don’ts.

For perishable foods, I regularly check the expiration dates. But even if it hasn’t expired yet and the food packaging seems swollen, or when the food is opened it looks or smells different than expected, I throw it in the trash without thinking twice, as it could be contaminated.

I never use the same cutting boards for raw and cooked foods. AND wash my hands before and after Handling any food is already instinctive.

One of my “never do” rules is to reheat cooked rice. It is because raw rice can contain spores of Bacillus cereus, a germ that poisons food. Although the Bacillus cells die when cooked, the spores survive. If the rice is allowed to cool and stand at room temperature, the spores develop into bacteria, the number of which will increase rapidly, since rice is a good culture medium for Bacillus at this temperature.

Bacillus grown on rice can produce toxins that, within hours of ingestion, can cause vomiting and diarrhea that last up to 24 hours.

I think that having a high level of awareness about food safety makes me be the first in line at buffets, eat breakfast with extreme caution in hotels and insistently look at the clock to see how often perishable foods are replenished.

The advantage of being a microbiologist is that one is very clear how to avoid food poisoning. And, of course, people blindly trust that what we cook at home is absolutely safe for consumption.

This article was originally published in English on The Conversation.

ABOUT THE AUTHOR

Primrose Freestone

Senior Lecturer in Clinical Microbiology, University of Leicester.