Within four hours of devouring a second serving of my homemade Ottolenghi tuna and cheese pasta recipe, my creation quickly emptied my body.
I had batch cooked three servings of the dish two weeks earlier and kept it in the freezer. Then, after a day thawing a serving in the fridge, microwaved for three minutes, and eaten, the night was punctuated with exhausting trips to the bathroom, and the next day fatigue was pushing me to the couch.
The vomiting, diarrhea and fatigue all pointed to a classic case of food poisoning—but Ottolenghi’s recipe was barely in the dock, as the first serving I’d had a fortnight earlier was delicious.
No, it must have been something I had done with the court ever since. Welcome to the food poisoning hazards of batch cooking.
As our retail budgets are squeezed by rising prices, more of us will make more money cooking large, low-cost pots of food to store and use later.
But there are rules for the process.
Within four hours of devouring a second serving of my homemade Ottolenghi tuna and cheese pasta recipe, my creation quickly emptied my body
Dr Matthew Gilmour, a microbiologist at the Quadram Institute (formerly the Institute of Food Research), based in Norwich, says tuna, cheese and pasta can all be frozen and reheated; what was wrong, he says, was my timing.
dr. Gilmour suspects I left the baking dish on the kitchen counter for too long before putting it in Tupperware and freezing it. I let it cool and rest at room temperature for three hours – and that had allowed the bacteria in the dish to multiply to harmful levels.
“Once food is cooked and cooled, wrap it up and put it in the freezer as soon as possible — within two hours,” says Dr. Gilmour. He recommends covering it with foil while it cools to prevent cross-contamination from, for example, a fly.
You’ll also need to transfer the food to a new dish, says Sylvia Anderson, a food hygiene consultant based in Wimbledon, south London, because leaving it in a warm bowl will take longer to cool, giving any bacteria that may be present time to grow. to grow.
I was not aware of such rules – and I am not the only one, it seems.
Last year there were 4,369 recorded cases of food poisoning in England and Wales, according to the UK Health Security Agency, but the majority of cases went unreported. A 2018 study by the Food Standards Agency estimated that there are in fact 2.4 million cases per year.
And the batch cooking trend may well push that figure up.
Sylvia Anderson says: ‘I’m amazed when I see people on Instagram [the social media platform] five-day batch cooked portions in the refrigerator.
As our retail budgets are squeezed by rising prices, more of us will make more money cooking large, low-cost pots of food to store and use later. But there are rules to the process
‘In the catering industry, pre-cooked food is only kept in the refrigerator for three days. After that it becomes unsafe, so it’s best to freeze the other two portions.’
Another major mistake people make is to keep things in the freezer for too long, she says. “In the industry, we say that ready-to-eat meals can be frozen for a maximum of one month.”
Sylvia suggests labeling foods with a date to track how long they’ve been in the freezer.
You also shouldn’t assume that freezing kills insects, cautions Dr. Gilmour. Microbes are only dormant and resuscitate once thawed. This means that you also need to be careful when defrosting food from your freezer.
“Leaving something on the side to thaw at room temperature increases the risk of microbes multiplying,” says Dr. Gilmour. “But most organisms can’t grow below 4c — the temperature in your fridge.”
Defrosting in the microwave can speed up the process, but stir the dish halfway through so it’s not just hot on the outside. Once safely thawed, reheat in the oven or microwave, making sure the dish is piping hot all the way through.
Frozen raw meat should never be thawed in the microwave, however, as the increased temperature can encourage bacterial growth – it’s best to thaw slowly in the refrigerator. And don’t be tempted to run the meat under hot water, as any microbes present can contaminate the sink and nearby utensils.
There is a long list of organisms that can cause food poisoning, says Dr Gilmour, ‘but the three most likely in the UK are salmonella, campylobacter and listeria’.
These are bacteria that live in soil and water, meaning animals that eat off the land are potential sources of contamination, as are vegetables grown in the soil or fertilized with the manure of infected animals.
Norovirus (known as winter fallow blight) is another common cause of food-related illness. But this is a virus, not a bacteria, so it won’t multiply in food. “A virus has to infect a living human or animal cell in order to reproduce,” says Dr Gilmour.
However, norovirus contaminates dishes with fecal spores on the hands of an infected person, so it is important to wash hands before preparing meals.
Microbes that penetrate the gastrointestinal tract attach themselves to the lining of your gut to survive. “This disrupts the ecosystem among the sheer numbers of healthy bacteria in your gut,” Dr. Gilmour says — and your body tries to expel the “bad” bacteria by vomiting.
The vomiting, diarrhea and fatigue all pointed to a classic case of food poisoning – but Ottolenghi’s recipe was barely in the dock as the first serving I’d had two weeks earlier was perfectly delicious
“But diarrhea can sometimes be an organism’s survival strategy — a means of escape and infecting others,” he adds.
Serious foodborne illness is rare, but the most vulnerable are the very old, the very young, or those undergoing treatment for other conditions, such as cancer.
Listeria (found in soft cheese or contaminated meat, for example) can travel to the brain to cause meningitis — an infection of the protective tissues (or meninges) surrounding the brain and spinal cord. Listeria can also cross the placenta of a pregnant woman and infect the fetus.
A campylobacter infection (often associated with undercooked chicken) can in rare cases lead to Guillain-Barré syndrome – a condition in which the immune system attacks nerves, causing severe movement problems in the limbs.
A friend of mine had this after a bout of food poisoning, possibly from a supermarket bought chicken meal from the oven. He endured a week of terrifying, bed-bound paralysis, then two years of mental stress, fatigue, and physical therapy to improve limited movement in his hands and feet.
dr. Gilmour says: ‘Cases like this are rare, but unfortunately they can take years to recover.’
Of course, most foodborne infections cause only mild symptoms of vomiting, diarrhea, and fatigue. The NHS advice is to rest and stay hydrated, but avoid sweetened drinks as bacteria can feed on the high sugar content.
However, prevention is always better than cure, and one food to be especially careful with when reheating is rice, which is home to bacillus cereus, a toxin-producing bacteria.
Takeaway rice could have been heated up in the restaurant once. “The rule in our house is that you should never cook, freeze, or reheat food more than once,” says Dr. Gilmour.
And be warned that a simple salad can also harbor bacteria.
‘I wouldn’t eat anything from my garden without washing it first,’ says Sylvia Anderson, ‘given the potential for contamination from bacteria in soil, animal droppings, dirt and worms.’
She recommends giving salads a “bath” in a mixing bowl of water with a teaspoon of salt to destroy any bacteria that may be present.
After 15 minutes, she says, the leaves will rise to the surface and leave the debris at the bottom.
Although my illness was unpleasant, I know from my friend who was afflicted with Guillain-Barré syndrome for a week that it could have been much, much worse.
But at least now I know how to cook in batches safely.