Listeria was detected in almost a quarter of frozen vegetable samples in England. Between December 2018 and April 2019, 1,050 frozen fruit and vegetable samples were collected for a health study. Listeria monocytogenes or other Listeria species were detected in 167 samples of vegetables, with Listeria monocytogenes was present in 10 percent of frozen vegetables.
The study of frozen fruit and vegetables from catering and retail premises in England assessed microbiological quality with respect to Listeria and E. coli. The findings were published in the International Journal of Food Microbiology.
Eleven samples contained more than 100 colony forming units per gram (cfu/g) of E. coli. Listeria monocytogenes or other Listeria species were detected in six samples of fruit and six fruit and vegetable mixes.
Work was prompted after the outbreak of listeriosis that affected 54 people in six countries with 10 deaths in 2015 to 2018 associated with frozen sweetcorn produced by Greenyard in Hungary. Researchers found the strain from this outbreak remained in the UK frozen vegetable food chain until April 2019 and caused a case of Listeria meningitis in England in February this past year.