Development of improved strategies to prevent enteric pathogen contamination of vegetables crops
Raw animal manure can contain zoonotic enteric pathogens (e.g. Salmonella, E. coli, Chryptosporidium). Inappropriate use of manure as fertiliser can result in such pathogens being transferred onto crops. Enteric pathogens have been shown to enter the food chain via contaminated vegetables and can cause severe and occasionally life threatening gastrointestinal infections in consumers.
Contamination risks are greatest for vegetables that are potentially eaten raw, especially when the vegetable grows close to or in the soil (e.g. lettuce, spinach, radish or carrots). Enteric pathogens are currently most frequently found on lettuce and spinach, which are crops in which the pathogens can be located in crevices or even within the plant tissues and/or stomatal cavities. Internal contamination is particularly serious, since it is extremely difficult to remove with standard sanitising agents.
A range of strategies has been suggested to reduce the pathogen transfer risk associated with manure use (composting of manure to reduce pathogen loads, alternative non-manure based fertility inputs, irrigation strategies which minimise splashing of soil onto crops, and use of weed control strategies based on thermal disinfections of the soil surface or physical barriers between soil and crop). Composting has frequently been shown to reduce substantially the survival of enteric pathogen, while there is little published information on the efficacy and reliability of the other strategies listed above. Many of the strategies proposed may have side effects on the sensory and nutritional quality of crops (e.g. changes to the fertility management see WP2.1 and WP3.3) and/or the environmental impact and sustainability of production systems (e.g. changes in fertility input type, soil disinfection strategies). It is therefore essential to quantify the effect of such side effects.
Using lettuce as a model crop we will carry out the following studies (sub-workpackages):
WP 3.4.1 Effect of fertility input types and levels and irrigation regimes on the risk of enteric pathogen transfer into the food chain and lettuce yield and quality
WP 3.4.2 Effect of weed management strategies on the risk of enteric pathogen transfer into the food chain and lettuce yield and quality
Environmental and sustainability audits and cost/benefit analyses on novel strategies developed under WPs 3.4.1 and 3.4.2 as part of Horizontal activity 1 & 2. This study will provide important data/deliverables for WP3.5 and SPs 5 & 6 (see graphic presentation)