[The risk of transmission of salmonellae in poultry farming: detection and prevention in Europe]

Abstract

While salmonellas can cause disease problems among poultry, they remain essentially a concern for public health, as a cause of outbreaks of food poisoning. The principal site of multiplication of these bacteria is the digestive tract, particularly the caecum, which may result in widespread contamination of the environment. The pathogenicity of salmonellas depends on the invasive properties and the ability of the bacteria to survive and multiply within cells, particularly macrophages. These properties are the source of vertical transmission which, in the case of survival of the embryo, can result in contamination of a flock or, in the case of embryonic mortality, can result in an explosion of contaminated eggs. Salmonella infection can be diagnosed by isolating the bacteria and/or serological testing of the flock. European Union Directive 92/117/EC, modified by Directive 97/22/EC, stipulates either the destruction of infected flocks of breeding birds, or decontamination of the flock in an effective way, before normal trade in products can be resumed. Noteworthy examples of effective measures suitable for prophylaxis of Salmonella infection in poultry flocks include the slaughter of infected breeding stock, the creation of sanitary barriers at building entrances, heat treatment of feed, the use of competitive exclusion, selection of breeds genetically resistant to Salmonella, and occasional vaccination and antibiotic treatment. However, the most effective means of reducing food poisoning remains adequate cooking of food and maintenance of the cold chain.