Scientists in Scotland have looked into how tackling foodborne pathogens in food producing animals could help reduce the consumption of contaminated meat.
The project, undertaken by Moredun Research Institute, reviewed the evidence on how pathogens enter the farm, are transmitted to livestock, and then spread into the farm environment.
A review of the literature showed several interventions that could be applied on-farm to reduce the risk of pathogens but there was a lack of compelling evidence to support any one method that demonstrates significant efficacy in reducing the occurrence and burden of specific pathogens.
Some multi-pathogen studies reported that certain strategies decreased levels of one pathogen while increasing or having no effect on others.
Management methods
Pathogens may enter a farm through routes such as introduction of new animals, contaminated machinery or vehicles, contact with wildlife, and through consumption of contaminated feed and water. Once in livestock, they can multiply, often in the gut of the animal and be shed in feces.
Management practices including biosecurity, cleaning and disinfection, stocking density and age groups, housing, bedding, flooring surfaces, and feed are important factors to consider when looking to reduce the risk from foodborne pathogens.
Hygiene and biosecurity practices involving mechanical cleaning and regular removal of soiled bedding material and fecal waste will help to reduce pathogen load. Handwashing, cleaning boots, and use of personal protective equipment are also important.
Some disinfectants can reduce bacterial agents and use of heat and steam cleaning will reduce infectivity of Cryptosporidium oocysts that are resistant to most common disinfectants.
Links have been shown between stress and susceptibility to disease. Livestock animals can become stressed due to a variety of factors, including heat, transport, feed withdrawal, clipping, shearing, dipping, lactation, and pregnancy. Species such as birds, rodents, and insects can carry and shed pathogens as well as spreading them between farms. Fencing can reduce transmission by restricting contact between livestock herds and wildlife. Seasonality can also influence risk with environmental conditions impacting the survival of pathogens.
Barriers to interventions include cost, time, complexity, lack of buy-in from farmers, legislative restrictions, conflicting advice and impact on farm management. Other factors influencing uptake are perceived futility of adopting practices unless they are taken up at national level, financial pressures from retailers, lack of support from government, lack of control of imported products, and differences in opinion on where responsibility lies for food safety.
Farmer survey
Changes to requirements and legislation driven by Brexit through agricultural reform or by initiatives related to net zero targets may limit or influence implementation of interventions.
Targeted interventions such as vaccination may be beneficial to tackle the spread and transmission of pathogens.
A survey of livestock farmers with 80 respondents showed most were more likely to use vaccination as an intervention strategy if it also gave protection against a production disease in their livestock compared with a vaccine that was being used to solely provide a public health benefit.
The majority of respondents had heard of the main pathogens covered in the survey; such as E. coli but were less aware of Cryptosporidium and Campylobacter. Almost three-quarters thought that pathogens are a problem for the industry but only 24 percent felt they were a problem for their own business.
The top three incentives for farmers to implement practices to reduce pathogens on farm were: reducing the risk of diseases that cause production issues in livestock, increasing the general health of animals, and improving safety of workers and family on farm. Cost and lack of information were seen as barriers to implementing new practices to reduce pathogens.
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