Scientists in Scotland have investigated how tackling foodborne pathogens in food-producing animals could help reduce the consumption of contaminated meat.
The project, carried out by the Moredun Research Institute, reviewed the evidence on how pathogens enter the farm, are transmitted to livestock and then spread in the farm environment.
Various interventions emerged from the literature review could be applied on the farm to reduce the risk of pathogens, but there was a lack of compelling evidence to support a method demonstrating significant efficacy in reducing the occurrence and burden of specific pathogens.
Some multi-pathogen studies reported that certain strategies reduced levels of one pathogen, while increasing or having no effect on others.
Management methods
Pathogens can enter a farm through routes such as the introduction of new animals, contaminated machinery or vehicles, contact with wildlife and through the consumption of contaminated feed and water. Once in livestock, they can multiply, often in the animal’s intestines, and be excreted in the feces.
Management practices including biosecurity, cleaning and disinfection, stocking densities and age groups, housing, bedding, floor surfaces and feed are important factors to consider in reducing the risk of foodborne pathogens.
Hygiene and biosecurity practices that include mechanical cleaning and regular removal of contaminated litter and fecal waste will help reduce pathogen burden. Washing hands, cleaning boots and using personal protective equipment are also important.
Some disinfectants can reduce bacterial agents and the use of heat and steam cleaning will reduce the 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 by a variety of factors, including heat, transportation, feed intake, clipping, shearing, dipping, lactation and pregnancy. Species such as birds, rodents and insects can carry and spread pathogens, as well as spread between farms. Fences can reduce transmission by limiting contact between herds of livestock and wildlife. Seasonality can also influence risk, with environmental conditions influencing the survival of pathogens.
Barriers to interventions include cost, time, complexity, lack of cooperation from farmers, legal restrictions, conflicting advice and impact on farm management. Other factors influencing its adoption include the perceived futility of adopting practices unless they are adopted nationally, financial pressure from retailers, lack of government support, lack of controls on imported products and disagreements over where the responsibility for food safety.
Survey among farmers
Changes in requirements and legislation resulting from Brexit through agricultural reforms or through initiatives linked to net zero targets could limit or impact the implementation of interventions.
Targeted interventions such as vaccination can be useful to tackle the spread and transmission of pathogens.
A survey of livestock farmers with 80 respondents found that most were more likely to use vaccination as an intervention strategy if it also provided protection against a production disease in their livestock, compared to a vaccine used solely to gain a public health benefit.
The majority of respondents had heard of the major pathogens covered in the survey; such as E. coli, but were less aware of Cryptosporidium and Campylobacter. Nearly three-quarters thought pathogens were a problem for the industry, but only 24 percent thought they were a problem for their own business.
The top three incentives for farmers to implement practices to reduce on-farm pathogens were: reducing the risk of diseases that cause production problems in livestock, improving overall animal health, and improving worker safety and family on the farm. Cost and lack of information were seen as barriers to implementing new practices to reduce pathogens.
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