Cryptosporidium has been discovered in pre-washed vegetables from major supermarkets in Kent.

Cryptosporidium was found in 17% of samples of pre-washed vegetables analysed by researchers in the School of Biosciences at the University of Kent.

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.

Dr Anastasios Tsaousis, Reader in Molecular and Evolutionary Parasitology and the research lead, said: ‘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.’

The research paper titled ‘Presence of Cryptosporidium parvum in pre‑washed vegetables from different supermarkets in South East England: A pilot study’ is published by Parasitology Research.