There’s an old saying that goes, we have to eat a peck of dirt before we die. These days, it’s taken to mean that we need to get dirty to build a strong immune system; something that goes hand-in-hand with the view that being ’too clean’ has depleted our gut microbes and compromised our immune system’s ability to deal with disease.

But embracing dirt doesn’t mean that we should be careless when cooking. If you don’t already take care in the kitchen, prepare to change your ways.


Bacteria such as Compylobacter, Salmonella, Listeria and Escherichia coli (E. coli) a re common causes of food poisoning, with Compylobacter responsible for more than 280,000 cases in the UK every year.1 Usually we get infected through food that hasn’t been stored or cooked properly, or through cross-contamination via hands, preparation surfaces and kitchen utensils.

Bacteria multiply through binary fission; meaning they grow and then split in half to

reproduce. This simple process of repeated grovvth and division makes it possible for bacteria colonies to grow very quickly: for example, given the right conditions, 1,000 germs can grow to im in under two hours. And the bigger the number, the bigger the chance of contracting food poisoning.

Studies have found, hovvever, that many of us are unwittingly encouraging harmful bacteria to thrive by making simple mistakes in the kitchen.

Keep cool

İn the UK, the maximum temperature recommended for fridges is 5C (The US FDA advises at or below 4C), but a recent Food Standards Agency (FSA) survey2 found that only 48 per cent of people questioned knew this. Low temperatures won’t kili bacteria, but will slow down the speed at which they multiply. The recommendation for 5C is specifically set because of Listeria, which grovvs nearly twice as fast at 8C than at 5C.3

The same FSA survey found that 58 per cent of us defrost meat or fish by leaving

it out at room temperature,2 providing bacteria with optimum conditions for growth. Meat should alvvays be defrosted in the fridge and kept away from other foods to avoid cross-contamination.


Ironically, fear of food poisoning may have led to a common, unsafe food practice. VVhilst it is tempting to wash meat, it’s not recommended. Katrina Levine, a registered dietician at North Carolina State University, told Optimum Nutrition: “VVashing meats and poultry can cause bacteria to splatter throughout your kitchen. When the vvater from your tap hits the meat, it catapults bacteria throughout your kitchen surfaces.” This means that bacteria that were previously living on the meat — and which vvould have been killed during the cooking process — are now spread throughout the kitchen where they can multiply.

Yet a recent study in the US found that some cookery books actually encourage the practice of vvashing poultry, and do not alvvays give good instructions.

Levine and her colleagues at North Carolina University evaluated food safety messages in 29 cookbooks that had appeared on the Nevv York Times best-seller list for food and diet books. The team looked at three key indicators: if the recipe said to cook the dish to a specific internal temperature; if given temperatures were safe; and whether recipes perpetuated unsafe food safety “myths” such as to cook poultry until the juices “run clear” — vvhich, the team argues, is an unreliable way to determine that meat has been cooked sufficiently.

The findings were less than encouraging; the team concluded that only 89 out of 1,497 recipes gave trustvvorthy information that readers could use to reduce the chances of contracting food poisoning.

Breeding bacteria

Hovvever, many of us do not know how bacteria thrive and survive. Providing meat has been slaughtered, processed, and stored in conditions that do not allovv bacteria to multiply and break down the meat fibres, bacteria should be confined to the surface. (Salmonello has been found inside chickens.) So if you like your steak pink in the middle, any bacteria should be killed with cooking. But if you decide to mince your uncooked steak and turn it into a burger, bacteria that was on the surface will be present throughout, and may survive if said burger isn’t cooked throughout.

As with the study on cookery books, research has also found that TV cookery shows might be encouraging poor practice. Dr Nancy Cohen, Professor of Nutrition at the University of Massachusetts Amherst, is the lead author of Compliance with Recommended Food Safety Practices in Television Cooking S/ıovvs, which reported that most hygiene practices across a range of TV cooking shovvs were outdated.

”Every episode we studied was out of compliance with the use of gloves,” says Cohen. “If you’re wearing gloves, you need to change them at every point that you’d wash your hands. If you’re not wearing gloves, you should be using utensils to touch ready-to-eat foods.”

Surprisingly, the hand-washing message is yet to reach everyone. The FSA survey found 14 per cent of respondents did not routinely wash their hands before preparing food.? Food safety consultant Dr Lisa Ackerley says research also shovvs that 50 per cent of office vvorkers don’t wash their hands after using the lavatory. “If people don’t wash their hands after going to the toilet they can transmit norovirus on kitchen and food surfaces.” So does the expression ‘”scuse fingers” suddenly resonate at ali?

Got it in the bag?

İt used to be common to find an occasional Caterpillar nestling among unvvashed salad leaves. These days we can eat salad straight from the bag. Yet some recent outbreaks of food poisoning have been traced back to bagged salad: in 2011, an outbreak affecting 2,000 people across Europe was traced back to bags of bean sprouts, and in 2016, an outbreak that killed two people was traced back to bags of rocket leaves.
İt was reported that one study found that the moist conditions inside a salad bag, combined with sugars, proteins and minerals from cut salad leaves, provided a breeding ground for bacteria. İt was also found that 100 Salmonella bacteria would increase to 100,000 vvithin five days.6
We don’t need to avoid bagged salads, but it is recommended to eat them on the day of purchase, and to avoid mushy leaves — if your bagged salad has started to look like the bottom of a svvamp, throw it away! And as with ali foods, if the packaging has bloated, get rid of it.
“Many people don’t realise that fruits and vegetables are a leading source of food-borne illness,” says Cohen. “Produce is ofterı eaten raw, so you can’t kili germs using heat. Ninety per cent of the [TV] shows we studied were out of compliance with the task of vvashing fruit and veg you must wash them before you cut, cook or serve them.”

Levine also advises to wash hands and make sure food is thoroughly cooked. “Wash your hands before you start cooking and after you handle raw meat, poultry, seafood or eggsshe says. “This is one of the best ways to help reduce the risk of cross-contamination when cooking at home, but only 4.3 per cent of the books we analysed mentioned hand washing or any other behaviour to reduce cross-contamination. Also, don’t rely on the temperatures in the books. You can only gauge if food is cooked by taking its internal temperature.” (Thermometers can be purchased with instructions on appropriate temperatures.)

VVhile it’s no myth that the young, old and infirm are more prone to food poisoning, a diverse range of gut microbes will help to fend off infection. Without a healthy microbiome, our defences are down. İn a new development, hovvever, we may not have to guess if vve’re at risk.

Dr Tim Spector, Professor of Genetics at King’s College London and director of the Department of Twin Research, says: “Gut infections are common in the young and elderly as gut diversity is often abnormal. When you’re ili, most drugs harm the gut microbes to some extent. If you’re worried, you can now test your own gut microbes with genetic testing — see I predict these tests will become routine vvithin five years.”

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