Experts have reviewed on-farm control options for Campylobacter in chickens raised for meat production and assessed advantages and disadvantages of each measure.

European Food Safety Authority (EFSA) experts considered 21 control options and seleced eight for further assessment because of their impact. The estimated effects of vaccination and application of feed and/or water additives appeared to be the highest.

Control options for broilers at primary production were assessed using risk assessment models and the work looked at the risk reduction in the number of campylobacteriosis cases attributable to eating broiler meat from the EU that could be avoided if a specific option is implemented in all farms across member states.

It was not possible to quantify the effects of combined controls because evidence‐derived estimates are inter‐dependent and there was a high level of uncertainty associated with each.

Regulation after opinion
The work is an updat on the 2011 EFSA’s opinion on Campylobacter following a request from the European Commission in 2018. After this opinion, the commission introduced a process hygiene criterion for Campylobacter spp. on poultry carcasses in slaughterhouses in 2018.

If 15 out of 50 samples of carcasses after chilling have counts above 1,000 colony forming units per gram, improvements in the slaughter hygiene, a review of process controls, and improvement in biosecurity measures must be done.

A previous EFSA opinion found handling, preparation and consumption of broiler meat may account for 20 to 30 percent of campylobacteriosis infections, while 50 to 80 percent may be attributed to the chicken reservoir as a whole.

According to the 2011 opinion, the public health benefits of controlling Campylobacter spp. in primary broiler production were expected to be greater than control later in the chain as the bacteria may also spread from farms to humans by other pathways than broiler meat.

Look at six control choices
A population attributable fraction (PAF) was calculated for six control options: hygienic anteroom, effective rodent control, having no animals in close proximity to the broiler houses, adding disinfectant to drinking water, employing few and well‐trained staff, and avoiding drinkers that allow standing water.

This analysis suggested adding organic acids, chlorine‐based biocides or hydrogen peroxide to drinking water could reduce risk of Campylobacter‐positive flocks by up to 55 percent. If effective rodent control was achieved on all broiler farms in Europe, prevalence of Campylobacter spp. in EU flocks could decrease by up to 19 percent, according to the studies analyzed.

The PAF analysis found restricting the number of employees and only using permanent or long‐term staff may reduce prevalence by up to 40 percent. If other animals are kept away from broiler houses or surrounding areas, the risk of Campylobacter‐positive flocks can be reduced by 88 percent, but most likely up to 45 percent, said experts.

“According to the PAF analyses calculated for six control options, the mean relative risk reductions that could be achieved by adoption of each of these six control options individually are estimated to be substantial but the width of the confidence intervals of all control options indicates a high degree of uncertainty in the specific risk reduction potentials,” according to the opinion.

Experts assess eight options
Use of bacteriophages requires more research, including field trials, before being considered a viable option for Campylobacter control in broilers. Reducing slaughter age would not work as practices vary between EU countries and because of welfare issues.

An updated modelling approach for feed or water additives or vaccination as controls found their effects were less than estimated in the 2011 opinion.

Expert knowledge elicitation tried to rank eight control options: vaccination; feed and water additives; discontinued thinning; employing few and well‐trained staff; avoiding drinkers that allow standing water; addition of disinfectants to drinking water; hygienic anterooms; and designated tools per broiler house. However, it was not possible to do this according to effectiveness based on expert judgements because of the large uncertainties involved.

Advantages of these options include ease of applying a hygiene barrier, adding additives to feed, improving bird health — e.g. biosecurity actions– better broiler welfare such as discontinued thinning — and cross‐protection against other pathogens including. drinking water treatments, feed additives.

Disadvantages may include a need for investment if structural changes are required to install an anteroom or lack of control as the farmer may not own the fields adjacent to the broiler house and cannot prevent other animals being close.

Another eight controls were judged to have a low probability of achieving at least a 10 percent reduction in campylobacteriosis. They were: effective rodent control, extended downtime between flocks, fly screens and keeping insects out of the broiler house, clean or amended litter, stocking density and flock size, the number of houses on site, selective breeding, and feed structure.