Campylobacter infection of broiler chickens in a free-range environment

Campylobacter jejuni is the most common cause of bacterial gastroenteritis worldwide, with contaminated chicken meat considered to represent a major source of human infection. Biosecurity measures can reduce C. jejuni shedding rates of housed chickens, but the increasing popularity of free-range and organic meat raises the question of whether the welfare benefits of extensive production are compatible with food safety. The widespread assumption that the free-range environment contaminates extensively reared chickens has not been rigorously tested. A year-long survey of 64 free-range broiler flocks reared on two sites in Oxfordshire, UK, combining high-resolution genotyping with behavioural and environmental observations revealed: (i) no evidence of colonization of succeeding flocks by the C. jejuni genotypes shed by preceding flocks, (ii) a high degree of similarity between C. jejuni genotypes from both farm sites, (iii) no association of ranging behaviour with likelihood of Campylobacter shedding, and (iv) higher genetic differentiation between C. jejuni populations from chickens and wild birds on the same farm than between the chicken samples, human disease isolates from the same region and national samples of C. jejuni from chicken meat

EFSA BIOHAZ Panel (EFSA Panel on Biological Hazards), 2013. Scientific Opinion on the public health hazards to be covered by inspection of meat (bovine animals).

A risk ranking process identified Salmonella spp. and pathogenic verocytotoxin-producing Escherichia coli (VTEC) as current high-priority biological hazards for meat inspection of bovine animals. As these hazards are not detected by traditional meat inspection, a meat safety assurance system for the farm-to-chilled carcass continuum using a risk-based approach was proposed. Key elements of the system are risk-categorisation of slaughter animals for high-priority biological hazards based on improved food chain information, as well as risk-categorisation of slaughterhouses according to their capability to control those hazards. Omission of palpation and incision during post-mortem inspection for animals subjected to routine slaughter may decrease spreading and cross-contamination with the high-priority biological hazards. For chemical hazards, dioxins and dioxin-like polychlorinated biphenyls were ranked as being of high potential concern; all other substances were ranked as of medium or lower concern. Monitoring programmes for chemical hazards should be more flexible and based on the risk of occurrence, taking into account the completeness and quality of the food chain information supplied and the ranking of chemical substances, which should be regularly updated to include new hazards. Control programmes across the food chain, national residue control programmes, feed control and monitoring of environmental contaminants should be better integrated. Meat inspection is a valuable tool for surveillance and monitoring of animal health and welfare conditions. Omission of palpation and incision would reduce detection effectiveness for bovine tuberculosis and would have a negative impact on the overall surveillance system especially in officially tuberculosis free countries. The detection effectiveness for bovine cysticercosis, already low with the current meat inspection system, would result in a further decrease, if palpation and incision are removed. Extended use of food chain information could compensate for some, but not all, the information on animal health and welfare lost if only visual post-mortem inspection is applied

Principles of some novel rapid dipstick methods for detection and characterization of verotoxigenic Escherichia coli

AIMS: The verotoxigenic Escherichia coli (VTEC) serotype most commonly associated with verotoxin (VT) production is O157:H7, but other serotypes have also been implicated in food-borne illness. These serotypes exhibit much greater genetic and biochemical diversity than E. coli O157:H7, making screening for all VTEC difficult. Here we describe development and testing of novel multi-analyte antibody-based dipstick methods for presumptive detection of VTEC cells and VTs, including non-O157 serotypes. METHODS AND RESULTS: The dipsticks are formatted as paddle-style and lateral flow devices. Test materials included raw milk, minced beef, apple juice and salami, spiked with VTEC. Prototype paddle dipsticks gave 47 of 48 E. coli O157-positive samples correct, and, simultaneously, 27 of 31 O26-positive samples correct, across the four food types. Prototype lateral flow dipsticks gave 12 of 12 E. coli O157-positive milk samples correct and, simultaneously, 28 of 28 positive VT samples correct. CONCLUSIONS: This work demonstrates that simple and rapid detection of more than one VTEC characteristic (toxin production and type, serogroup) is possible in a single dipstick test device, directly from a food enrichment culture. SIGNIFICANCE AND IMPACT OF THE STUDY: The development of simple easy-to-use rapid methods for simultaneous detection and preliminary characterization of VTEC will enable the risk presented by all VTEC to be more thoroughly assessed (e.g. in surveillance studies, outbreak investigations)