Salmonella control: A global perspective

Salmonella in poultry is a global issue. The poultry industry and regulatory bodies however, do not respond to it in the same manner everywhere. In western as well as exporting countries control measures have been implemented; sometimes voluntary by the poultry industry, sometimes forced by a governmental regulation. Below a short overview.

By Rick van Oort, Ceva Sante Animale, France

Salmonellosis is one of the most prevalent zoonotic diseases in humans. In Europe alone over 100,000 cases are reported each year and in the United States there are approximately 40,000 cases reported annually. Since many milder cases are not diagnosed or reported, the actual number of infections may be over thirty times higher. The most important serovars found are Salmonella Enteritidis (SE) and Salmonella Typhimurium (ST), both of which are often linked back to poultry products. Examples include the 2010 massive egg recall in the US due to SE-contaminated eggs, and more recently, the Salmonella Heidelberg contamination of ground turkey meat in the US. These incidents prove that Salmonella control in poultry remains important to guarantee safer food production for consumers.

Control of Salmonella not easy

Control of Salmonella in poultry is not easy because there are many variables to be controlled. In short the following control measures are of importance:
  • Bio-security: It is imperative to control farm hygiene, feed, water, and especially rodents, as they can be main sources of infection. Good bio-security starts with a simple list of all subjects (feed, water, personnel, insects, rodents, etc.) moving in or out the house, followed by a list of actions to disinfect or control these subjects.
  • Monitoring and sampling: Layer and broiler flocks must be free of at least SE & ST; for breeders, other Salmonella serotypes also require control. Increased sampling of the environment – boot swaps and throughout the farm environment – easily indicates if flocks are positive for Salmonella. Further sampling is required to discover the source of infection and initiate an intervention program.
  • Vaccination: Inactivated or live vaccines to control Salmonella are increasingly used around the world as they are proven to be an important step in reducing shedding of Salmonella within a flock. Other intervention methods include feed additives, water treatments, etc.
  • Poultry carcass treatment: While this practice is commonly used in the US and other countries, it is forbidden in the EU. In conjunction with other controls, it is an effective tool to reduce the risk of Salmonella contamination in poultry meat.
  • Global experiences on Salmonella

    Europe - Based on 2004-2005 Salmonella contamination baseline studies in breeders, layers, broilers and turkeys, the EU implemented a number of strong precautious regulations to reduce Salmonella contamination in poultry and poultry products. The implemented regulations are based on increased sampling in production and rearing periods by using environmental samples (boot swaps, manure and dust) as the reference.

    EU directive 2160/2003 aims to reduce Salmonella levels in poultry, and prescribes a target for maximum Salmonella levels in broilers, layers, breeders and turkeys. Within this directive other instructions detail sampling protocols and timing for each of the poultry species, setting clear goals for annual reduction of Salmonella levels according to the base line study. Each member state in Europe has established specific National Control Plans (NCP) to address compliance with EU directives.

    The EU directive focuses on the reduction of Salmonella Enteritidis and Salmonella Typhimurium in live broilers, layers and turkeys. Breeders must also reduce the levels of Salmonella Hadar, Salmonella Infantis and Salmonella Virchow.


    The implementation of these regulations resulted in a great reduction of flock contamination with Salmonella, for example, SE and ST positive cases in broilers decreased from 11% to 0.7% over a five year period. Fresh broiler meat contamination has decreased from 9.4% to 5.4%. In layers, SE and ST levels dropped from 20.4% to 3.2%, while recently table eggs showed only 0.5% positive cases for SE and ST. Since the implementation of strong regulations to reduce Salmonella in European poultry, the number of human Salmonellosis cases dropped significantly (Figure 1).

    USA - Last year, the Food & Drug Administration (FDA) initiated a new set of regulations to reduce Salmonella Enteritidis levels in eggs, while the US Department of Agriculture (USDA) also launched a regulation to control all Salmonellae in poultry meat.

    The new regulations orders the layer industry to focus on taking environmental samples in the rearing (14 weeks) and production (40-50 weeks) period, as well as post-moult. A positive environmental sample leads to extensive egg testing. In case these egg samples prove to be positive all eggs from the flock must be diverted for pasteurisation, which results in a lower income for the producer.

    Right after the introduction of these new regulations, the US egg industry was confronted with an egg recall due to SE-contaminated eggs. The recall was widely covered by the media, causing a loss of consumer confidence in eggs and egg products and subsequently a decrease in egg prices. The event triggered the United Egg Producers (UEP) 5 Star program, which specifically advises vaccine types and prevention tools for the control of Salmonella.

    For the broiler meat industry the new regulation included the implementation of 51 bird sample sets allowing a maximum of five out of 51 positive for Salmonella serotypes known to cause disease to humans. Processing plants are rated in categories based on the positive carcass counts from these sample sets. As soon as processing plants have more than five positives out of 51 sample sets, the plant names are published on-line and more samples are to be taken. While the majority of processing plants are currently below the 5-in-51 positive carcass threshold, large broiler integrators are operating conservatively by relying on more vaccines to reduce the Salmonella contamination before the broilers enter the processing plant.

    Latin America - The Brazilian poultry meat industry depends largely on export, so the majority of breeders are vaccinated for Salmonella to reduce broiler Salmonella levels. In other Latin American countries large integrators also, to a certain extent, use vaccines in breeders and use other control tools to reduce Salmonella levels in broiler meat.

    The control of Salmonella in layers is gaining interest as egg producers move to brand their products in stores where one recall can destroy the egg producer’s brand. Some producers also see the control of Salmonella in eggs as a tool for premium branding. The use of vaccines to control Salmonella Gallinarum is practiced in many countries in Latin America.

    Asia-Pacific - As in Latin America, exporting broiler meat integrators in countries such as Thailand are using Salmonella vaccines in breeders and other measurements to safeguard poultry meat.

    In Japan, Salmonella control continues to be an important topic, as the country ranks as one of the highest consumers of eggs in the world. Japanese consumers eat a large portion of their eggs raw, making Salmonella control even more important. In the Pacific region the use of vaccines is more common.

    Russia, Ukraine and Commonwealth of Independent States (CIS) – In Russia, Ukraine and other CIS states, new Salmonella reduction regulations closely resemble the testing protocols and measurements used in the EU. As Russia increases the production of poultry meat to reach higher levels of selfsufficiency and Ukraine is preparing to export more products into Europe and surrounding countries, Salmonella control of poultry products will become vital.

    Africa & Middle East - In Africa and the Middle East, the interest in Salmonella control is slowly growing. Breeders in the MAGREB area and Egypt more and more implement zoonotic Salmonella control programs, while layer integrators in other countries remain focused on Salmonella Gallinarum/Pullorum control. Regulators in many countries don’t consider Salmonella to be a risk to public health. Here integrators also face regulatory roadblocks regarding the use of vaccines.

    Conclusion

    The importance of controlling Salmonella in poultry is gaining more interest and is mainly driven by:
    • Increased regulation for the control of Salmonella such as in the EU and US
    • Increased export regulations and barriers, making control of Salmonella vital for broiler integrators exporting broiler meat
    • Increased branding of poultry meat and eggs makes that Salmonella contamination can do great damage to the brand and the company, affecting future sales
    • Human Salmonellosis outbreaks are the trigger for strong regulations and control measurements.