Scientific Opinion on the risk posed by Shiga toxin‐producing Escherichia coli (STEC) and other pathogenic bacteria in seeds and sprouted seeds

Abstract

Sprouted seeds are young seedlings obtained from the germination of seeds. They are ready-to-eat foods which have caused large outbreaks. The bacterial pathogens most frequently associated with illness due to contaminated sprouted seeds are Salmonella and to a lesser extent STEC. Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus and Yersinia enterocolitica have also been transmitted by sprouted seeds, albeit very rarely. Dry seed contaminated with bacterial pathogens has been identified as the most likely initial source of sprout-associated outbreaks; although other routes of contamination (e.g. during production due to poor practices) may also occur. In some outbreaks, contamination of seeds with as low as 4 Salmonella per kg was sufficient for the sprouts to cause disease. Seeds purchased by sprouts producers are usually not grown specifically for this purpose. They may be contaminated during production, harvest, storage and transport, and there may be difficulties in traceability of seeds from production to sprouting. Bacterial pathogens on seeds may survive for long periods during seed storage. There is so far no guarantee of a bactericidal step which is able to control contamination of seeds with bacterial foodborne pathogens acquired prior to germination. Due to the high humidity and the favourable temperature during sprouting, bacterial pathogens present on dry seeds can multiply on the sprouts. Contamination with pathogenic bacteria must be minimized by identification of seed crops intended for sprouted seeds production before planting, and application of GAP, GHP, GMP, HACCP principles at all steps of the production chain. The relevance of decontamination treatments of seeds and of microbiological criteria is also discussed. © European Food Safety Authority, 2011 KEY WORDSDecontamination techniques, foodborne pathogenic bacteria, Salmonella, seeds, Shiga toxinproducing E. coli (STEC), sprouted seeds, microbiological criteria, mitigation options. SUMMARYThe European Commission asked the Panel on Biological Hazards to issue a scientific Opinion on the public health risk of Shiga toxin-producing E. coli (STEC) and other pathogenic bacteria that may contaminate seeds and sprouted seeds and in particular the Panel was asked: (i) to assess the public health risk caused by STEC and other pathogenic bacteria that may contaminate both seeds and sprouted seeds intended for direct human consumption; (ii) to the extent possible, to identify risk factors contributing to the development of STEC and other pathogenic bacteria that may contaminate these seeds and sprouted seeds; (iii) to recommend possible specific mitigation options, and to assess their effectiveness and efficiency to reduce the risk throughout the food chain (from the seed production until final consumption); and lastly, (iv) to recommend, if considered relevant, microbiological criteria for seeds and sprouted seeds, water, and other material that may contaminate the seeds and sprouts throughout the production chain.On the assess...

Sprouts and Microgreens: Trends, Opportunities, and Horizons for Novel Research

“…The most common agents causing outbreaks in relation to sprouts consumption include Salmonella, Escherichia coli O157:H7, and Shiga-toxin-producing E. coli [128,129,131,132]. Instead, other bacterial pathogens (e.g., Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, and Yersinia enterocolitica) have rarely been reported [131,133]. Indeed, Salmonella and E. coli O157:H7, unlike Listeria monocytogenes, can internalize into seedlings, thus, making ineffective simple washing treatments or topical disinfectants [129,134].…”

“…Indeed, Salmonella and E. coli O157:H7, unlike Listeria monocytogenes, can internalize into seedlings, thus, making ineffective simple washing treatments or topical disinfectants [129,134]. Consequently, pre-harvest interventions could effectively enhance the microbiological safety of sprouts [129], even in the absence of a validated Critical Control Point (CCP) intended to at least reduce levels of the fecal pathogen to acceptable standards [131,133,135].…”

Plant-Microbe and Abiotic Factors Influencing Salmonella Survival and Growth on Alfalfa Sprouts and Swiss Chard Microgreens

“…Seed sprouting provides an excellent environment for the growth of microorganisms, including foodborne pathogens (14,15). In fact, a level as low as 4 most-probablenumber (MPN) Salmonella organisms per kg of seed was determined to be capable of causing a foodborne outbreak associated with sprouts (16). Unlike sprouts, microgreens so far have not been associated with any foodborne outbreaks.…”

A Review on the Rising Prevalence of International Standards: Threats or Opportunities for the Agri-Food Produce Sector in Developing Countries, with a Focus on Examples from the MENA Region

“…As such, the EFSA, mandated by EC regulation 178/2002 to inform and assess the risks along the food chain, was asked to provide scientific opinions on the public health risk posed by pathogens on food of non-animal origin (FNAO). A total of six opinions have been issued on FNAO as of 2011, referring to the following food/pathogen combinations with a similar production system and identified as the most important risks within FNAO [24,62,63,64]:The risk from VTEC in seeds and sprouted seeds (urgent request after VTEC crisis)The risk from Salmonella and norovirus in leafy greens eaten raw as saladsThe risk from Salmonella and norovirus in berriesThe risk from Salmonella and norovirus in tomatoesThe risk from Salmonella in melonsThe risk from Salmonella , Yersinia , Shigella , and norovirus in bulb and stem vegetables, as well as carrots…”