Researchers in Europe have tested produce for the presence of a parasite with findings showing more information is needed to help put mitigation measures in place.

Scientists estimated the prevalence of Toxoplasma gondii oocysts in commercially available ready-to-eat (RTE) salad mixes in 10 European countries.

They collected 3,329 salad samples from October 2021 to September 2022. The prevalence of Toxoplasma gondii contamination was 4.1 percent. Further analysis revealed that winter season, sampling, and packaging of salad in Northern Europe and production in Western Europe were associated with detection of the parasite, with no statistically significant differences between salad types.

The detection method used did not quantify oocysts, confirm their presence visually or test them for viability and infectivity. 

According to the study published in Eurosurveillance, research was needed because consumption of RTE salads is growing; there is no mandatory surveillance for foodborne parasites in fresh produce; and current methods have inconsistencies and limitations.

Seasonal impact
Infection with Toxoplasma gondii may go unnoticed or be associated with mild clinical signs. However, people with weakened immune systems can develop severe neurological and respiratory symptoms, which may result in death. Infections during pregnancy can cause congenital toxoplasmosis leading to spontaneous abortions or fetal malformations.

Samples of baby leaves, cut and mixed salad were collected in the Czech Republic, Denmark, France, Germany, Italy, Norway, Poland, Portugal, Spain and the United Kingdom.

Of the 3,293 samples, 135 were positive for at least one target gene. The majority of positive results were from samples collected in winter with 59.

Most positive samples listed packaging countries as the UK, France, Portugal, Spain and Denmark. Some samples had no information on origin, while 37.5 percent came from Italy, Portugal and Spain in Southern Europe. Samples from Western Europe had the highest percentage of positives, but there was no significant difference between regions.

Scientists said the results provide evidence of contamination in RTE leafy greens in Europe, which poses a potential risk for consumers. 

“As Toxoplasma gondii DNA was detected in commercially available RTE salad mixes in many European countries, we need to better understand the production systems to assess the associated risks and implement prevention and control measures. This is particularly relevant since RTE salads are intended to be consumed raw without any further treatment by the consumer,” they added.