After the Devon tainted water scandal, scientists find cryptosporidium parasites in pre-washed supermarket vegetables… but they REFUSE to reveal which stores they came from

By Liam On Jun 19, 2024

Almost a fifth of pre-washed vegetables on supermarket shelves in Britain could contain a parasite found in contaminated faeces, a study suggests.

Scientists have found traces of cryptosporidium, the same parasite responsible for an outbreak that affected more than 100 people in Devon last month and caused severe stomach upset, in 17 percent of so-called ready-to-eat vegetables.

Experts behind the study did not want to reveal which supermarkets had the contaminated vegetables, as they instead wanted to raise awareness about the supply chain that leads to this contamination, rather than specific points of sale.

But they told MailOnline that the level of risk was likely to be the same across the sector and that any ‘pre-washed’ or ready-to-eat vegetables should be treated with suspicion.

Cryptosporidium is normally contracted through drinking water contaminated with infected human or animal feces, such as the outbreak in Devon earlier this year. However, you can also get it from food.

Experts from the University of Kent found cryptosporidium in 17 percent of so-called ready-to-eat vegetables bought in supermarkets

Cryptosporidium parasites are protected by a thick shell that allows them to survive even in chlorinated swimming pool water

This usually happens when vegetables have been grown in infected manure and not washed thoroughly enough or if a person infected with the parasite has been involved in food preparation.

In their study, experts from the University of Kent analyzed 24 samples of pre-washed vegetables collected from four supermarkets in Canterbury in 2023.

Four of these (17 percent) tested positive for traces of cryptosporidium.

Although these vegetables have been washed with water containing disinfectants, cryptosporidium is resistant to this and can therefore survive this process.

This is significant, because eating just a small amount of cryptosporidium, just 10 oocysts, the form the parasite takes to survive outside a host, is enough to make someone sick.

The experts behind the study could only detect ‘traces’ of the parasite and could not confirm whether enough oocysts were present to cause disease.

What is Cryptosporidium?

Cryptosporidium, also known as Crypto, are small parasites that live in water and enter the body through food or drink.

They cause a disease called cryptosporidiosis, with the most common symptom being watery diarrhea. It can also cause nausea, vomiting and fever.

Symptoms usually last about two weeks, but can last longer. Young children and people with weak immune systems are at greater risk of being more seriously affected.

The parasites are protected by a thick outer shell that allows them to survive outside the body. They can live for several months in cool, moist conditions.

They are also resistant to chlorine so can live in swimming pools for up to a week.

Outbreaks of cryptosporidiosis have been linked to drinking or swimming in contaminated water. Food prepared with contaminated water, such as salads washed with it, can also pose a hazard.

Farmers who handle livestock may also be at risk, as the infection can be contracted from cows, goats and sheep, especially lambs.

Once swallowed, the Cryptosporidium shells break open and release the parasites.

However, some parasites will pass through a person’s digestive system intact, so infection can occur by ingesting fecal particles from an infected person, for example by changing a sick baby’s diapers.

Infected people can shed up to 100 million parasites in one bowel movement. Swallowing just ten is enough to make you sick.

The UK Health Security Agency (UKHSA) provides advice on controlling cryptosporidiosis outbreaks and monitors outbreaks to find the source.

Dr. However, Anastasios Tsaousis, lead author of the study and an expert on parasites, told MailOnline that there is likely to be some risk with all types of pre-washed vegetables.

“Any product that comes from the environment, for example exposure to soil and water, has the same risk,” he said.

This is partly because such vegetables are processed in central facilities before being distributed across the country.

He added that he would advise all Britons to wash such vegetables themselves again to reduce the risk of exposure.

Dr. Tsaousis also said the team’s discovery suggested improvements need to be made in the processing of these vegetables.

“The presence of cryptosporidium in pre-washed vegetables could mean a re-examination of the sanitation practices applied by suppliers in the production chain, such as improved hygiene measures during harvest, processing, packaging, transport and storage,” he said.

‘There is also a need for greater awareness among consumers about adequate storage of vegetables and washing hands before eating.’

Suggested methods include ensuring that all water used in vegetable supply chain preparations is thoroughly boiled before use, or other disinfection methods are used, such as using ozone for added safety.

The authors, who published their work in the journal Parasitological researchsaid the presence of cryptosporidium in pre-washed vegetables was concerning given that people were increasingly relying on these products as a healthy food option.

“In recent years, ready-to-eat vegetables have become increasingly attractive to consumers, as they conveniently provide healthy food that requires no preparation,” they wrote.

They suggested that other research could investigate how exactly vegetables become contaminated further down the supply chain.

Doctors technically call a cryptosporidium infection cryptosporidiosis.

Patients often have to tolerate these symptoms for two weeks before they finally disappear from their system.

But some patients may experience longer periods of illness in people with weakened immune systems, such as cancer patients.

Victims may also experience periods of false hope where their symptoms disappear for a few days, leading them to think they have finally gotten over the infection, only for it to return.

Most people with cryptosporidiosis are not offered treatment and are instead told to drink plenty of fluids.

Patients with the infection are told to stay away from work and school until they are symptom-free for at least two days, to avoid passing the bug to others.

The food safety of produce bought on supermarket shelves is receiving increasing attention after hundreds of Britons were struck by a rare strain of E. Coli linked to contaminated lettuce leaves, prompting a mass recall of produce.