The Food Safety Authority of Ireland and safefood have this week released findings from a comprehensive study which shows a potential low-level risk of illness for consumers who eat non-ready-to-eat frozen vegetables, fruits, or herbs without prior cooking.
The microbiological study analysed almost 1,000 samples of frozen vegetables, fruits, and herbs for the presence of Listeria monocytogenes, Salmonella, Listeria spp and E coli. Listeria monocytogenes was found in 27 of the samples tested (three per cent ), the majority of which were non-ready-to-eat frozen vegetables (21 samples ).
The FSAI and safefood stress that while the figures were low for the presence of Listeria monocytogenes, it is a potential health risk for people who may eat these non-ready-to-eat frozen foods uncooked frequently, and/or if consumer preparation and handling practices allow Listeria monocytogenes, if present, to grow to levels high enough to cause listeriosis.
The consumer research part of the study surveyed 815 people across the island of Ireland and found that 80 per cent said they regularly eat frozen vegetables, 40 per cent eat frozen fruits, and 13 per cent eat frozen herbs. While most (68 per cent ) said they would cook the product before eating, 32 per cent said they regularly eat one or more types of frozen vegetables, fruits, or herbs without cooking them.
Strawberries, blueberries, raspberries, and mixed berries were the frozen fruits most likely to be eaten uncooked in a dessert or in a smoothie. A smaller number of consumers said they would regularly eat uncooked non-ready-to-eat frozen vegetables such as sweetcorn, carrots, peas, peppers, and spinach in a salad or as a garnish.
The FSAI and safefood advise that all non-ready-to-eat frozen vegetables, fruits and herbs should be cooked prior to eating and in accordance with the cooking instructions on the label. If these products are eaten uncooked by people who are immunocompromised, pregnant, the elderly, or young children, there is risk of serious illness.
Symptoms of Listeria monocytogenes infection can include mild flu-like symptoms, or gastrointestinal symptoms such as nausea, vomiting, and diarrhoea.