A HIGHLY-contagious parasite has been found in pre-washed vegetables from several major supermarkets.
Cryptosporidium, which can cause diarrhoea and vomiting, was present in 17 per cent of samples analysed by scientists across Kent.
The study, carried out by the University of Kent’s School of Biosciences, warned families should take extra care when consuming ready-to-eat products.
Cryptosporidium is a water-borne and food-borne parasite that causes an infection called cryptosporidiosis.
Over the last few months, it has affected people and farm animals across the UK, causing diarrhoea, vomiting, stomach pains, fever, headaches and fatigue.
Several people have been hospitalised.
Cryptosporidium is typically found in lakes, streams, rivers and untreated drinking water, but it can be present in food.
There is evidence of infections from eating and drinking unpasteurised milk, undercooked meat and offal (liver, kidneys, and heart), but research into the presence of cryptosporidium in pre-washed and ready-to-eat vegetables in the UK is limited.
The study, published in Parasitology Research, looked at 36 pre-washed vegetables purchased from four major supermarkets in Canterbury between May and July 2023.
Samples were randomly chosen from packaged ready-to-eat varieties, and duplicates from each were obtained.
Twelve samples were excluded as not enough DNA could be extracted.
But of the remaining 24, 58 per cent tested positive for cryptosporidium, and 17 per cent (four) produced similarities to cryptosporidium parvum – the leading cause of human cryptosporidiosis.
While many people will experience mild symptoms, infections can be life-threatening – particularly for young children.
“Infection is associated with failure to thrive, malnutrition, cognitive deficits, and stunting in infants and children so efforts to prevent infection and outbreaks should be strictly enforced,” the authors said.
The Food Standards Agency (FSA) recommends re-washing ready-to-eat vegetables to ensure they are safe and avoid getting ill.
The source of the parasite isn’t clear, but it could be present in irrigation water or fertilisers, or transfer during harvesting, processing, packaging or transportation, the authors said.
“This pilot study could unlock a potential common source of cryptosporidium infection across the various regions in the UK,” they added.
“The vegetables from individual chain supermarkets are packaged in their own central facilities and subsequently distributed nationwide.
“While pre-washed and ready-to-eat vegetables undergo more thorough washing with water containing chlorine disinfectants compared to unpackaged vegetables, cryptosporidium particles (oocysts) are actually resistant to disinfection with chlorine and can only be reliably removed by boiling water or filtration.
“So, they are expected to be free from parasites and ready-to-eat straight from the packaging, but some oocysts remain and are likely to cause illness.
“Our study could contribute to developing better strategies to prevent infection with cryptosporidium.
“Further studies could focus on tracking the exact point of contamination and addressing it.”
By Lizzie Parry, Head of Health
ANYONE who’s had a bout of norovirus will know how miserable a tummy bug can be.
In this case, the cause appears to be the cryptosporidium parasite, a tiny organism that causes an illness known as cryptosporidiosis.
The bug can be found in the intestines and poo of infected humans and animals.
Anyone can fall sick but it’s most common in kids aged between one and five.
Other people at high risk include people who work with animals, people exposed to human faeces (parents changing nappies), and people who swim in open water.
That’s because you catch the bug from an infected person or animal by coming into contact with their faeces.
Other sources of infection include drinking or swimming in contaminated water, eating contaminated fresh food (unwashed or unpeeled veg or salads) and drinking contaminated raw milk.
Like norovirus, the symptoms can be really unpleasant, watery diarrhoea, stomach pains, nausea or vomiting, fever and a loss of appetite, which can lead to dehydration.
Symptoms tend to last for about two weeks but can ease off and reappear in that time.
The only way to know for sure if you’ve been infected – and to tell it from other tummy bugs – is to ask the doctor to test a stool sample.
Like other infectious bugs, there are things you can do to protect yourself and your family.
First and foremost, wash your hands thoroughly with warm soap and water before handling any food, after preparing raw food, after going to the loo or changing a baby’s nappy and after playing with, or looking after any animals – including your pets.
And if you, or a member of your family, catches the bug make sure you wash all dirty bedding and towels, avoid sharing towels, clean all bathrooms and avoid preparing food for others until you’ve been symptom-free for at least 48 hours.
It goes without saying that if you have symptoms avoid going into work or taking your children to school until you’ve been symptom-free for 48 hours too.
There’s no specific treatment, but most healthy people will recover within a month. The NHS notes it is important to drink lots of fluids to avoid dehydration.
If you are worried about your child, or you can’t seem to shrug off the bug it’s worth speaking to your GP – try filling out an online consultation form.
Dr Anastasios Tsaousis, research lead, added: “Whilst our 2023 study cannot distinguish between live and inert cryptosporidium, it is nevertheless important in that the presence of cryptosporidium in pre-washed vegetables could mean revisiting the sanitation methods employed by suppliers along the chain of production such as improved hygiene measures during harvesting, processing, packaging, transportation and storage.
“There is also a need for increased awareness among consumers on the adequate storage of vegetables and handwashing before eating.”
As wekll as through food, you can get cryptosporidiosis directly from another person or animal by touching faeces, (for example when changing a nappy) and putting your hands near or in your mouth without washing them thoroughly.
It also spreads from infected animals, or by swimming in or drinking contaminated water.
