Food safety and antibiotic resistance

2019-10-17

As the world is celebrating the World Food Day, it is well worth considering the impact of antibiotics and antibiotic resistance on safe food. Food safety is also linked to the sustainable development goals, in particular Sustainable Development Goals 2 - Zero Hunger and 3 - Health and Well-being.

Safe, nutritious and sufficient – SDG 2 – Zero Hunger

The first target of Sustainable Development Goal (SDG) 2 is to “end hunger and ensure access by all people, in particular the poor and people in vulnerable situations, including infants, to safe, nutritious and sufficient food all year round.” Safe food means that the food should not make us sick, and not contain things hazardous to our health. These hazards can be classified as physical, chemical or microbiological. WHO has estimated that 600 million people fall ill globally due to foodborne diseases. More than 400,000 of them die, and one third of these fatalities are children under 5 years of age. Microbiological hazards are generally due to contamination with pathogens such as bacteria, but it is also important to recognize the impact of antibiotic resistance in these pathogens.

Microbiological hazards

Commonly, microbiological hazards are related to food contaminated by a variety of bacterial species like Salmonella sp. Campylobacter sp., Listeria sp., Bacillus cereus or Escherichia coli. While some microbiological hazards are clearly visible on the food through spoiling, not all hazardous foods are visibly spoiled. Bacteria and other microbes that spread through foods such as meat, vegetables and other fresh produce are called food-borne pathogens. Infectious foodborne diseases acquired from contaminated raw or cooked food are major causes of mortality and morbidity globally. Most commonly, foodborne pathogens cause diarrheal diseases.

In meat, foodborne pathogens are often a result of suboptimal infection control and biosecurity. Bacteria carried by the animals in for example their gastrointestinal tracts, can contaminate the meat during slaughter or in butcher shops. In the case of vegetables or produce, contaminants come from the soil, manure or irrigation water.

Antibiotics in the food chain

To ensure safe and sufficient food, antibiotics and disinfectants are used in a variety of ways in food production. In some cases, antibiotics are even used as preservatives in for example milk and seafood, and antibacterial substances may also be used in efforts to maintain the safety of crops. Antibiotics are still used to promote growth of animals in many parts of the world, prophylactically to prevent disease and to treat sick animals. This use of antibiotics in animals accounts to a majority of the global antibiotic use (by weight), but also creates a legitimate conflict of interest. On the one hand, there is the interest of farmers to make a living, and the perception that routine antibiotic use is necessary for safe and effective production. And on the other hand, there is the interest to reduce antibiotic use to limit antibiotic resistance. Correctly used, antibiotics can treat sick animals, and enable sustainable production of safe food.

Feces and urine from animals are often used as manure in agriculture. Unless properly treated, the manure may still contain fecal bacteria from the animals. These bacteria, together with bacteria that occur naturally in soil, may then contaminate the crops. Also, if the water source for irrigation is unsafe, pathogens from the water may also contribute to the contamination.

Antibiotic resistance as a food safety matter

When antibiotics are used injudiciously, whether by humans or in food animals, this increases the development and spread of resistance and the risk that the antibiotics used will actually be ineffective. But similarly, antibiotics that are used control diseases in animals may become ineffective due to antibiotic resistance. In some instances, this will lead to increased animal suffering and decreased production, spread of antibiotic resistance in the foodborne pathogens in production herds and, as a consequence, to antibiotic resistance in the foodborne infections.

As noted above, foodborne infections are a major cause of the global burden of disease. While non-invasive diarrhea is mostly not appropriate to treat with antibiotics it remains a major source of antibiotic misuse, and treatment of invasive infections relies on antibiotics. As an example, an outbreak of 3816 cases with an uncommon variant of E. coli (enteroaggregative and producing Shiga toxin) via contaminated sprouts was reported in Germany in 2011. The bacterium caused a severe infection, 20% of the patients developed hemolytic-uremic syndrome and 54 patients died. The strain was resistant to beta-lactam antibiotics, including third-generation cephalosporins and was partially resistant to fluoroquinolones. Treatment options were carbapenems and ciprofloxacin.

What can we do?

Food safety is an important issue, and action needs to be taken on many different levels, for example:

• Use antibiotics judiciously, both in food production and in humans.
• Prevent infections, by for example handwashing, kitchen hygiene and improving hygiene in animal production.
• Ensure that the water sources are safe, and remain safe.

Maintaining access to safe food is vital for everyone and requires constant efforts in quality control, surveillance and hygiene. And when the worst happens, access to healthcare and effective antibiotics is vital to save lives.