EU Survey of Pathogens in RTE Plant-Based Foods Suggests Microbial Growth Potential, Need for Regulatory Attention
A Europe-wide survey of ready-to-eat (RTE) plant-based dairy, meat, and fish substitutes found that, while the products generally had satisfactory microbiological quality, isolated samples tested positive for pathogens and elevated microbial counts warranted attention from industry and regulatory authorities. Additionally, analysis of the physico-chemical properties of these foods suggested that RTE plant-based products could support microbial growth.
Published by the European Food Safety Authority (EFSA), the report detailed a collaborative retail prevalence survey conducted across 15 EU Member States. The work was funded by EFSA through its Focal Point Tailor-made Activities program, but the report noted that its conclusions were those of the authors and should not be considered an output adopted by EFSA.
National competent authorities collected 1,533 RTE plant-based products retail samples, which were tested at or near the end of their labeled shelf life by participating laboratories.
Overall, the researchers found that the microbiological quality of the tested products was mostly satisfactory. However, cheese and meat substitutes had more microbiological quality issues than plant-based milk and cream substitutes, potentially indicating hygiene or processing problems during manufacturing and/or inadequate cold-chain maintenance.
Foodborne Pathogen and Hygiene Indicator Results
Testing varied by microorganism based on participating laboratory capacity. Analyses for important foodborne pathogens revealed:
- Listeria monocytogenes was detected in just one of 1,533 samples—specifically, a chilled oat-based milk substitute—at less than 1 colony-forming unit per gram (CFU/g). No measurable growth was observed when the product was analyzed near the end of its “Best Before” date.
- Salmonella was not detected in any of the 1,332 samples tested.
- Shiga toxin-producing Escherichia coli (STEC) was detected in five of 831 samples by PCR, but viable organisms were not confirmed by culture, and the samples were therefore not determined to be unsatisfactory.
- Bacillus cereus or Bacillus spp. were detected in 17 of 1,113 samples tested, of which 14 were classified as borderline unsatisfactory, with levels between 1,000 and 100,000 CFU/g. The other three positive samples exceeded 100,000 CFU/g and were classified as unsatisfactory. The findings occurred primarily in meat and cheese substitutes. Notably, five Bacillus-positive samples with levels above 1,000 CFU/g used tofu as their primary plant-based ingredient, including two samples classified as unsatisfactory. The researchers said this finding could suggest contamination from raw materials, temperature abuse, and/or handling issues during manufacturing.
- Clostridium perfringens or Clostridium spp. were detected in 99 0f 810 samples (12.2 percent) at borderline unsatisfactory levels. No samples exceeded the unsatisfactory threshold of 10,000 cfu/g.
Analyses for hygiene indicator microorganisms were also conducted. The researchers found:
- Listeria spp. (other than L. monocytogenes) was detected in 15 of 1,533 samples (0.98 percent), including one dairy cream, four cheeses, and ten meat substitutes. One fermented-cauliflower Camembert alternative contained an unsatisfactory level of Listeria spp. at 3,100 CFU/g.
- E. coli occurrence was low, but levels exceeding 100 CFU/g were found in six samples: three cheeses and three meat substitutes. One cashew-based Camembert alternative contained elevated levels of both E. coli and B. cereus.
While the presence of Listeria spp. may not constitute a regulatory non-compliance, the report explained, it indicates contamination potential and highlights the importance of robust hygiene controls and environmental monitoring, particularly for RTE plant-based products. Additionally, unsatisfactory results of E. coli (above 100 CFU/g), although not itself a food safety hazard, can indicate fecal contamination of raw materials.
Product Characteristics Could Support Pathogen Growth
The researchers also assessed the products’ physico-chemical characteristics because, they explained, contamination alone does not determine risk; whether a food can support microbial growth is also important. Of the samples evaluated, 68.7 percent (976 of 1,421) had a pH of at least 5.1, and 92.9 percent (1,034 of 1,113) had a water activity (aw) of at least 0.94, meaning the characteristics of many products would not generally prevent microbial growth.
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The report's literature review reinforced the findings of the present survey. Although most previously published studies reviewed by the researchers indicated that RTE plant-based substitutes met microbiological safety standards, L. monocytogenes, B. cereus, and Staphylococcus aureus were detected in small numbers of samples in recent European surveys. Documented outbreaks of listeriosis and salmonellosis have also been associated with RTE plant-based dairy substitutes.
The Need for Industry and Regulatory Attention
Based on the findings, the researchers called for continued monitoring and targeted risk assessment of RTE plant-based substitutes.
The report also noted inconsistencies among EU Member States in their national microbiological criteria for RTE plant-based foods, suggesting that harmonized standards could promote more consistent official assessments of the microbiological quality of such products.
