Influence of agronomic practices and pre-harvest conditions on the attachment and development of Listeria monocytogenes in vegetables

Interest in fresh vegetables is on the increase due to their protective effects against several diseases. Listeria monocytogenes is a human pathogen easily found in vegetables. The purpose of this review article is to analyse the influence of the agricultural practices applied in pre-harvest, the environmental biotic and abiotic factors characterising the cultivation field, as well as the handling procedures at harvest that might greatly influence the presence and the levels of L. monocytogenes in fresh produce. This review article describes the routes of L. monocytogenes infections in relation to the agricultural practices commonly applied during vegetable cultivation. It also analyses the influence of the different cultivation systems as well as the main environmental factors and compares the effects of manual and mechanical harvest retrieving data from literature. Even though post-harvest sanitising is a common practice, fresh produce is still responsible for foodborne diseases. In the last years, the number of cases of human listeriosis is on the increase, and the consumption of fresh vegetables is being more frequently associated with these events. While still relatively rare, human listeriosis is one of the most serious food-borne diseases and continues to be one of the more lethal foodborne pathogens associated with vegetables. Seed decontamination represents an efficient operation to reduce microbial plant internalisation and diffusion. Since L. monocytogenes persists in soil for long periods, the hydroponic systems have been found to reduce its contamination of vegetables.