Toxocara eggs found on spinach from English farms
What it found
In lab tests, about a quarter of spinach samples from four commercial farms in southern England carried DNA from Toxocara roundworm eggs.
The eggs were found on leaves, and the authors say washing spinach before eating it matters.
What they found
Toxocara on spinach
Overall, 25.0% of the 120 spinach samples tested positive for Toxocara. T. canis was found in 23.0% of samples and T. cati in 1.7%.
Differences between farms
The share of positive samples varied widely between the four farms, from 7.4% to 45.5%. The authors say this difference was statistically significant.
Which animal likely
More T. canis was found than T. cati. The authors say foxes and dogs are the likely main source of the eggs on these farms, since foxes are usually infected with T. canis.
Rain and soil splash
The farm with the most positive samples was sampled after heavy rain. The authors say rain can splash soil onto low crops, which may have moved eggs onto the leaves.
Eggs may not be infective
The DNA test cannot show whether the eggs were developed enough to cause infection. The authors say they could not tell if the eggs found had the potential to infect people.
What the authors conclude
“The results of this study highlight the requirement for the thorough washing of vegetables prior to their consumption, especially those such as spinach which may be eaten without first peeling or cooking, and effective farm biosecurity measures to minimise access to farmland by definitive host species of Toxocara spp.”
Also in their conclusions
- They say the results show Toxocara eggs were present on spinach leaves grown on commercial farms in the south of the UK for public consumption.
- They stress that thoroughly washing vegetables before eating them is crucial, especially for vegetables often eaten without peeling or cooking.
- They advise improving farm biosecurity to keep dogs, cats and foxes away from farmland, and treating domestic pets for worms, to reduce contamination of soil and crops.
How it was done
Toxocara eggs from dogs, cats and foxes can cause blindness and brain damage if people accidentally swallow them. Earlier UK work had only looked at small community gardens, so the authors wanted to check spinach grown on larger commercial farms that supply many people.
They collected 120 samples of spinach, each 300 g, from four commercial farms in Surrey, Berkshire, Greater London and Buckinghamshire between June and August. Each sample was tested in the lab using a sieving method followed by a DNA test for T. canis and T. cati.
What it can’t tell you
- The DNA test cannot show whether the eggs found were alive or able to cause infection in people.
- The study only looked at four farms in southern England, so the results may not apply to other regions or other vegetables.
Who paid
- Funding
- Funded by Biotechnology and Biological Sciences Research Council (from the PubMed record).
- Conflicts
- The authors declare no competing interests.
- Authors work at
- University of Surrey, UK; Queen's University, UK
The paper
- Title
- From fox to fork? Toxocara contamination of spinach grown in the south of England, UK
- Type
- Study
- Summarised from
- Full text
- Cite
- Healy SR, Morgan ER, Prada JM, Betson M (2023). From fox to fork? Toxocara contamination of spinach grown in the south of England, UK. Parasites & vectors. doi:10.1186/s13071-023-05674-8Free full textPubMed 36732821DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error