Priority combinations of hazards and produce
Fruits and vegetables are not inherently contaminated by biological hazards, but these are introduced at later stages. The faecal-oral route of contamination is a key concern meaning that faecal contamination on the produce is consumed and results in illness of the consumer (JIFSAN, 2010). There are a wide range of hazards that can be transmitted faecally-orally with fruits and vegetables as vehicles, including viruses, bacteria and protozoan parasites. In the EFSA opinion “Microbiological hazards associated with the use of water in the post-harvest handling and processing operations of fresh and frozen fruits, vegetables and herbs (ffFVHs). Part 1 (outbreak data analysis, literature review and stakeholder questionnaire)” (EFSA, 2023), the hazard prioritization was based on reported outbreaks in the EU (2014−2020) and a literature review. The most relevant microbiological hazards identified were: (i) L. monocytogenes, Salmonella spp., and human pathogenic E. coli, which were found to contaminate a wide range of fruits and vegetables, with a high impact on morbidity (number of hospitalisations) and mortality (number of deaths). Leafy greens and sprouted seeds were the most common vehicles, but tomatoes, cucumbers, pre-cut zucchini, plums and pre-cut melon were further implicated in Salmonella outbreaks. (ii) Enteric viruses − mostly norovirus − were identified in several outbreaks with frozen berries as implicated food vehicles, causing most cases overall. Norovirus outbreaks were also associated with fresh berries and leafy greens; Further, hepatitis A virus has been implicated in outbreaks with fresh strawberries and dates (PHAS, 2026). (iii) Other hazards which caused three or more European outbreaks associated with fruits, vegetables and herbs during that seven-year period were Yersinia spp., Shigella spp., and Cryptosporidium parvum, most often with leafy greens as vehicles (EFSA, 2023).
Contamination and cross-contamination along the food chain
As stated above, fruits and vegetables are themselves not associated with human pathogens, but they are introduced to the produce from external sources. This contamination can occur during any phase of the production and handling chain. Most products can be contaminated in primary production, especially by zoonotic hazards transmitted faecal-orally, e.g., Salmonella spp., pathogenic E. coli, Cryptosporidium parvum, and Yersinia spp. (EFSA, 2023) from inadequately treated manure, soil, contaminated irrigation water, wild animals and pests, dust or workers’ hands (JIFSAN, 2010). In some listeriosis outbreaks, the outbreak investigations reported that contamination occurred at the processing plant or packing house; however, bacteria could potentially have entered the processing plant from the primary produce in low (undetectable) numbers and thereafter have multiplied (EFSA, 2023). There is less information on the route of foodborne virus contamination, but enteric human viruses may contaminate fruits and vegetables all along the production chain, most often from human handling operations (EFSA, 2023), even though wastewater contaminated irrigation water was suspected in an outbreak with frozen raspberries (Mäde et al., 2013). In any case, apart from viruses – due to lack of evidence − most hazards are already supposed to have contaminated the fruit or vegetable in question before primary packaging.
Pathogen and spoilage growth potential
Bacteria that have contaminated fresh produce may be able to reproduce on the surface of the product or within the product if the tissue has been injured. The bacterial growth rate is determined by several factors such as nutrient availability, pH, water activity (available water), temperature and oxygen (Alegbeleye et al., 2022, Skandamis, 2025). Considering pathogenic bacteria, biological competition (for available nutrients and colonisation space) from present microbiota is another important factor that can limit growth of harmful hazards (Alegbeleye & Rhee, 2024). Unless the plastic packaging has a modified atmosphere or preventive substances (see for example Hasan et al., 2024) the growth rate of pathogens (and spoilage organisms) should not be significantly different in packaged compared to bulk environment since the intrinsic factors and extrinsic factors are basically the same. A (non-modified) plastic packaging can in fact make the extrinsic environment more prone to microbial (mould, yeast and bacterial) growth and mycotoxin production (Alegbeleye et al., 2022). In fact Siroli et al. (2017), measured a faster decline of added pathogens and spoilers in cardboard materials than in plastic, which was due to the entrapment of microbial cells within the fibres and the pores of the cardboard materials. Physical damage to the produce may favour growth of pathogens as well as spoilage microbiota due to the release of nutrients and the exposure of surfaces that favour adherence of microorganisms. Studies have shown that Salmonella and pathogenic strains of E. coli reached population sizes 10 times higher in wounded compared to intact tissues (AESAN, 2023). Hence, there may be an indirect benefit of packaging in relation to food safety and spoilage.