Salmonella

Introduction

Salmonella is a bacterium that can cause an illness called salmonellosis in humans. This is a zoonotic disease, which means it can be transmitted directly or indirectly between animals and humans.

Salmonellosis is the second most common zoonotic disease after campylobacteriosis in the EU, and Salmonella is a common cause of foodborne disease outbreaks.

In the EU, over 91,000 salmonellosis cases are reported each year. EFSA has estimated that the overall economic burden of human salmonellosis could be as high as €3 billion a year.

Symptoms of human salmonellosis include fever, diarrhoea and abdominal cramps. If it infects the bloodstream it can be life-threatening. Salmonella is commonly found in the intestines of healthy birds and mammals.

In foods, it is most frequently found in eggs and raw meat from pigs, turkeys and chickens. It can spread to humans through contaminated foods.

Safe handling of raw meat and other raw food ingredients, thorough cooking and good kitchen hygiene, can prevent or reduce the risk posed by contaminated food.

Latest

After several years of decline, salmonellosis cases in the EU have flattened out. In 2017 the number fell slightly from 94,425 to 91,662 but the downward trend that began in 2008 has stalled in recent years.

This is one of the main findings of the latest annual report on trends and sources of zoonoses published by EFSA and the European Centre for Disease Prevention and Control (ECDC).

EFSA’s role

An integrated approach to food safety

To protect consumers from Salmonella, the EU has adopted an integrated approach to food safety from farm to fork. The approach consists of both risk assessment and risk management measures involving all key actors: EU Member States, the European Commission, the European Parliament, EFSA and ECDC. The approach is supported by timely and effective risk communication activities.

This approach helped to reduce human cases of salmonellosis in the EU by almost one-half over five years (2005-2009). In 2003, the EU set up an extended control programme for zoonotic diseases, with Salmonella a priority. All EU Member States implemented enhanced Salmonella control programmes in poultry, and risk managers set targets for the reduction of Salmonella in poultry flocks (e.g. laying hens, broilers, turkeys). Restrictions were also imposed on the trade of products from infected flocks.

EFSA provided scientific advice on the impact of setting reduction targets for Salmonella in poultry and analysed progress made in the EU towards meeting the targets.

EFSA plays an important role in protecting consumers from this public health threat by providing independent scientific support and advice on food safety-related aspects of Salmonella. It collects and analyses data on the prevalence of Salmonella in animals and foods; assesses the food safety risks for human health and advises on control and mitigation options.

EFSA’s findings are used by risk managers in the EU and the Member States to monitor the situation, to define control measures and to set or review reduction targets for Salmonella in the food chain. They are also used by risk assessors such as EFSA’s Panel on Biological Hazards to provide risk estimates.

EFSA is assisted by the network for zoonoses monitoring data, a pan-European network of national representatives and international organisations that assist EFSA by gathering and sharing information on zoonoses in their respective countries.

Annual monitoring of Salmonella in animals and food

EU-wide data on the presence of Salmonella in the food chain as well as the prevalence of Salmonella in animals and human salmonellosis are collected and analysed in annual EU summary reports prepared by EFSA and ECDC.

These reports analyse data from the monitoring of Salmonella in animals, Salmonella in food and microbiological food safety end process hygiene criteria, and human salmonellosis collected by Member States.

EU-wide surveys on the prevalence of Salmonella

EFSA produces EU-wide baseline survey reports on the prevalence of Salmonella in food and food-producing animals, including chickens, turkeys and pigs, and on the risk factors that contribute to the prevalence of Salmonella in animal populations.

EFSA is also responsible for determining the technical specifications for these harmonised EU-wide surveys.

Risk assessments and recommendations

EFSA evaluates the food safety risks of Salmonella and provides scientific advice on control options at the request of risk managers or on its own initiative. It also assesses the impact of setting new EU-wide reduction targets for Salmonella in various animals.

Milestones

February 2019 ­EFSA scientists assess current EU reduction targets for Salmonella and say that setting stricter targets in laying hens at farm level could help reduce cases of this origin by a half.

December 2017 ­The declining trend of salmonellosis cases in the EU has levelled off according to the annual report on zoonotic diseases.

March 2015 Over the past four years EFSA has looked closely at the risks posed by pathogens that can contaminate foods of non-animal origin, such as fruit, vegetables, cereals and spices. The top-ranking combinations of foods and pathogens are Salmonella and leafy greens eaten raw, followed by Salmonella and bulb and stem vegetables; Salmonella and tomatoes; Salmonella and melons; and pathogenic E. coli and fresh pods, legumes or grains.

July 2014 EFSA’s opinion on public health risks from eggs says that extending the storage time of eggs at home or at retail would increase Salmonella food poisoning risks. Experts focussed on the risk to consumers posed by Salmonella Enteritidis, the bacterium responsible for causing the highest number of egg-borne outbreaks in EU.

April 2012 EFSA evaluates the impact on public health of reducing Salmonella levels in turkeys across the European Union. Experts say that a reduction of Salmonella levels in 2012 to 1% or less for all the serovars considered in the model in fattening turkey flocks would result in an estimated 2.2% reduction across the EU of all cases of human salmonellosis compared to 2010.

March 2011 EFSA and ECDC publish their annual report on zoonoses and foodborne outbreaks in the European Union for 2009. The report shows that Salmonella cases in humans fell by 17% in 2009, marking a decrease for the fifth consecutive year.

April 2010 EFSA assesses the public health risks from Salmonella in pigs and the impact of possible control measures. Pigs and pig meat may be responsible for 10 to 20% of all human cases of salmonellosis in the EU – but with differences between countries. Controlling Salmonella more effectively within the pig meat food chain has a direct impact on reducing the number of human cases.

April 2010 Experts say that concerning eggs from laying hens, the type of Salmonella most frequently associated with human illness is by far Salmonella Enteritidis. They found a linear relationship between the number of Salmonella Enteritidis positive flocks in the different Member States and the number of eggs contaminated with this microorganism. This implies that a reduction in the number of positive flocks would result in a proportional reduction in the number of contaminated eggs.

March 2010 Results of a survey on Campylobacter and Salmonella in chicken at slaughterhouses in the European Union show that in most EU Member States a high prevalence of Campylobacter is found in chickens, whereas Salmonella is less frequently detected. This was EFSA’s sixth baseline survey on foodborne bacteria carried out at EU level and the first to directly investigate the presence of Campylobacter and Salmonella in chickens at slaughter.

December 2009 The results of an EU-wide survey on Salmonella in breeding pigs indicate that Salmonella is commonly detected in holdings with breeding pigs in most EU Member States. The report recommends further studies on surveillance for Salmonella in breeding pigs.

December 2008 EFSA evaluates Salmonella contamination of pigs at slaughter. Whilst the results revealed that Salmonella infected pigs were more likely to lead to Salmonella contaminated carcasses, these could also come from uninfected pigs.

October 2008 EFSA publishes an analysis of risk factors related to Salmonella in flocks of turkeys. The document will serve as a scientific basis to assist Member States in defining the best control measures for reaching the new Salmonella reduction target set by the European Commission.

2007 to 2008 EFSA publishes results of EU-wide surveys on Salmonella levels in slaughtered pigs, in turkeys and in chicken reared for meat.

2006 to 2007 EFSA publishes results of EU-wide surveys on Salmonella levels in laying hens

EU framework

The monitoring and control of foodborne zoonoses as well as food hygiene requirements and food safety criteria are regulated by EU legislation. For details on the regulatory framework, see the topic on foodborne zoonotic diseases.