A recent announcement by the United Kingdom’s Food Standards Agency made runny eggs safe once more for vulnerable sectors of the population. More than 30 years after a shock remark from junior health minister Edwina Currie sank the British egg industry, UK Lion Mark eggs are now effectively free from salmonella and thus safe for pregnant women, the elderly and the very young.
Salmonellosis is the most frequently reported foodborne disease worldwide, with more than 1.2 million cases reported each year in the United States. Spread easily by ingestion, it causes gastroenteritis, which can be severely debilitating or fatal in vulnerable patients when it crosses into the bloodstream. During outbreaks, it is important to note not just presence of the pathogen but also its specific serovar, as this information is useful in tracking down the source.
The UK Lion Code of Practice is a big success story in food safety and domestic egg production. In the early 1990s, producers took a proactive stance to overturn the bad press, instituting health and flock welfare initiatives to win back British consumer trust. It’s been a long journey, but the initiative seems to have worked. Today, more than 90% of UK eggs are produced under the scheme. Although microbial testing is still required under European Union Commission Regulation (EC) No. 2073/2005, the scheme can safely declare Lion Mark eggs as virtually salmonella–free.
Salmonella “freedom” was achieved by implementing a rigorous system of routine testing, welfare and husbandry improvements, extensive vaccination of all poultry, and careful monitoring at all steps in the egg-laying chain from producer to retailer. The British Lion scheme, overseen by the British Egg Industry Council (BEIC), meets the ISO 17065 international accreditation standard, which is far more stringent than either European Union or UK current legislation. The scheme covers the following:
- Breeding flocks: regular testing and slaughter for positive identification of Salmonella ser. Enteritidis and Salmonella ser. Typhimurium
- Pullet rearing: vaccination against the Salmonella species plus records that accompany all birds on transportation showing origin, hygiene and pest control measures
- Feed control: mandatory exclusion of ingredients sourced from mammals and birds, plus measures aimed at preventing on-farm contamination
- Registration: records accompany birds through the chain, with traceability for all individuals and their products
- Audits: independent and self-audit schedules include unannounced visits by scheme regulatory officials on farm
- Staff training: includes welfare and husbandry measures designed to promote animal health and prevent infection, with contingency plans to cope with emergency situations
- Packing center controls: strict hygiene controls with record keeping that shows regular egg testing from each farm of origin (at least 20 eggs per farm per quarter year)
- Egg mark: only eggs produced under the scheme show the red Lion mark stamped on the shell, giving origin, production method and date for consumer information
- Cool chain maintenance: records show maintenance of appropriate storage throughout the egg cycle, from flock to consumer
- Laying farm conditions: regulations cover flock health and animal welfare routines designed to avoid Salmonella infection and contribute to its early detection
Although the United States does not have an accredited egg mark scheme, the US Department of Agriculture (USDA) maintains oversight on the poultry industry through Food Safety and Inspection Service (FSIS) programs. Historical records show that S. Enteritidis and S. Typhimurium cause half of all US salmonella infections in people; this information informs most of the sampling initiatives in place.
FSIS runs a surveillance plan for liquid and frozen egg products. It includes regular sampling to monitor disease incidence, with schedules determined by previous processing plant and farm salmonella isolation.
The National Poultry Improvement Plan (NPIP), established in the 1930s, aims to maintain health in the US national flock. The NPIP’s first mandate was to reduce levels of S. Pullorum infection, which, with 80% chick mortality, severely reduced chicken rearing. The scheme has since moved into wider flock disease prevention, but it also oversees poultry disease zoonoses, including Salmonella species. Testing routines establish disease-free flocks, with culling and removal where infection is found.
As with many food safety schemes, monitoring relies on accurate microbial testing and identification in products and also the production environment. NPIP-approved salmonella testing includes the Applied Biosystems™ TaqMan® Salmonella Enteritidis Real-Time PCR Assay (Thermo Fisher Scientific) for egg and environmental samples. The Thermo Scientific™ SureTect™ Salmonella Species PCR Assay (Thermo Fisher Scientific) is validated for a range of complex food matrices, including poultry meat and raw eggs. In addition, a new real-time PCR test, the Thermo Scientific™ RapidFinder™ Salmonella species, Typhimurium and Enteritidis PCR Kit, has recently been released for use in the US market. The new multiplex test was recently awarded AOAC-RI Performance Tested MethodsSM certification for simultaneous detection of the three Salmonella targets in poultry and pork products as well as production environment samples. The validation program will extend to address salmonella testing needs at all stages of the poultry and pork production process in the near future, complementing other solutions as part of Thermo Scientific’s integrated “farm to fork” approach for poultry testing.
Learn more about testing for foodborne pathogens in our food microbiology testing community.