Did you know that Salmonella strains can survive in water for several months? Thus, such harmful bacteria can be found in drinking water as well as various food products in contact with contaminated water.
How dangerous for human health can be a Salmonella infection?
According to the European Food Safety Agency (EFSA), Salmonella is a bacterium which can cause illness to consumers in contact with contaminated food or water. The induced disease, called Salmonellosis, is a zoonosis: it is transmissible between animals and humans. In its annual report about zoonosis, zoonotic agents and food borne outbreaks, EFSA states that Salmonella is the first cause of food borne outbreaks (including waterborne outbreaks) in the European Union. In 2016, 1,067 Salmonella outbreaks were reported. Moreover, with 94,530 cases in 2016, salmonellosis is the second most reported foodborne illness in the EU. While the number of cases tended to decline until 2014, it leveled off between 2014 and 2016 (+3%).
According to the World Health Organization (WHO), someone who drinks water or eats foods contaminated by Salmonella can develop the following symptoms: fever, abdominal cramps, diarrhea, nausea and sometimes vomiting. This disease usually occurs from 6 to 72 hours after the contamination and lasts 2 to 7 days. Salmonella bacteria can strongly impact immune systems of both elderly and infants and lead to dehydration, hospitalization and death. Every year, 550 million cases of Salmonella contamination are reported in the world (almost 1 in 10 people) and 33 million of healthy lives are lost.
How does Salmonella contaminate water?
We often hear of Salmonella contaminating animal products, but water and raw foods such as fruits and vegetables are not immune to this risk.
Salmonella strains live in the intestinal tract of infected humans and warm blooded animals: they are mostly contaminating humans through meat and animal products. However, they may also migrate in soils and water as millions of germs can be released in a bowel movement of an infected organism.
According to the CDC (Centers for Disease Control and Prevention in the United States), contaminated waste can enter the water with a higher probability with factors including sewage overflows, sewage water systems that are not working properly, polluted storm water runoff and agricultural runoff. Salmonella bacteria are ubiquitous and hardy and can survive several months in water.
Thus, foods such as fruits and vegetables can be subsequently contaminated or cross-contaminated because of irrigation or process water. Drinking water like tap water or private wells can also be contaminated. In this case, end consumers can be advised by health department to use bottled water or to boil water before drinking it or using it for brushing teeth, washing dishes, making ice, cooking, drinking and making baby formula.
What precautions can be taken by food players to avoid water contamination?
According to the WHO, food handlers must make sure they use safe water. For example, fruits and vegetable growers need to evaluate and manage risks from irrigation water and aquaculture producers have to manage water quality.
EFSA’s experts state that food producers and manufacturers should:
- comply with Good Manufacturing Practices (GMP),
- comply with recommended codes of practices and guidances such as Codex guidelines,
- apply Good Agricultural Practices (GAP), notably regarding water supplies,
- pay specific attention to the selection of water sources for irrigation and agricultural chemical application (notably of pesticides and fungicides),
- avoid the ingress of sewage Salmonella contaminated water.
In case of Salmonella contamination, it is possible to implement, among others, the following interventions:
- efficient drainage systems to take up excess overflows,
- water treatment at primary production and processing steps to prevent the additional dissemination of contaminated water (for instance, the risk of cross-contamination during washing fruits and vegetables can be reduced if disinfectants are properly used within the washing tank and water tested before use),
- periodic testing of indicator E. coli micro-organism for fecal contamination in irrigation and process water to adapt preventive measures.
You want to know more about Salmonella and matrices at risk?
In Mérieux NutriSciences Blue Paper 2018, you will access to deep focus on Salmonella with information about products contributing to exposure, associated risks, preventive measures, important events in 2017, unique RASFF (Rapid Alert System for Food and Feed) statistics, norms and regulatory perspectives. You will access to similar focus on other contaminants and food matrices, with information on associated risks and RASFF statistics.
- CDC, Salmonella and Drinking Water from Private Wells, July 2015.
- EFSA, Foods of non-animal origin: what are the risks?, March 2015.
- EFSA, Salmonella cases no longer falling in the EU, December 2017.
- EFSA, Scientific Opinion on the risk posed by pathogens in food of non-animal origin. Part 2 (Salmonella and Norovirus in tomatoes), January 2014.
- EFSA, ‘The European Union summary report on trends and sources of zoonoses, zoonotic agents and food‐borne outbreaks in 2016’, December 2017.
- Food Safety Agency of Ireland (FSAI), Factsheet: Salmonella species, September 2011.
- Interagency Food Safety Analytics Collaboration (IFSAC), Report: Foodborne Illness Source Attribution Estimates for Salmonella, Escherichia coli O157 (E. coli O157), Listeria monocytogenes (Lm), and Campylobacter using Outbreak Surveillance Data, February 2015.
- NBCNEWS, Salmonella outbreak linked to tap water, March 2008.
- USDA, Salmonella Questions and Answers, August 2013.
- World Health Organization (WHO), Factsheet: Salmonella (non-typhoidal), January 2018.