Antimicrobial resistance in food products

Antimicrobial resistance in food products is a public health challenge with implications for global food safety. Unsafe food causes an estimated 600 million illnesses and 420,000 deaths annually. Food-borne pathogens, such as Salmonella species and Campylobacter species, demonstrate direct transmission of resistant bacteria. The prevalence of antimicrobial-resistant food-borne pathogens in food samples is greater than 10%, frequently exhibiting multidrug resistance.

Antimicrobial resistance in commensal bacteria

Monitoring and surveillance of antibiotic resistance from farm to fork highlight commensal bacteria as significant reservoirs. Bacteria acquiring resistance genes through horizontal gene transfer occur more often in these populations, acting as vectors to transfer them to bacteria of clinical importance.

Antimicrobial resistance in animal pathogens

Animal-derived food is a major reservoir for resistant pathogens. While certain bacterial infections in animals have become more difficult to treat, untreatable infections are not yet widespread. Knowledge on resistance in animal pathogens remains minimal, lacking studies demonstrating that this creates treatment problems with a direct impact on food production.

The public health impact of antimicrobial resistance in food

The role of food as a vehicle for transmission is not always clear, particularly for commensal bacteria. Zoonotic food-borne pathogens transmit resistance directly to humans via food, indicating a substantial public health risk, though distinguishing food-borne from direct contact routes remains difficult.

Risk analysis models

Multiple quantitative microbial risk assessment models, such as ComBase, have been developed for food-borne pathogens to estimate contamination levels. However, these face challenges due to data limitations. Based on tentative models assessing human exposure, the risk at the quantitative level may not be too large, while molecular analysis shows direct contact with positive animals may bring a higher risk.

The public health impact of resistance in animal bacteria

Commensal and animal-specific pathogenic bacteria contribute to indirect transfer, potentially affecting both animal and human health. The acquisition of resistance genes by bacterial populations in animals obscures the inference of gene transfer directionality.

An example of reduced resistance in animals and impact on food products

Regulatory interventions have successfully reduced antimicrobial practices. Following the 1969 Swann report recommendations, the use of antimicrobials for growth promotion has been prohibited in many countries. For example, avoparcin use stopped in the late 1990s, demonstrating the impact of targeted restrictions.

Antimicrobial resistance and food production

The application of antimicrobials in livestock production for therapeutic, prophylactic, and growth promotion purposes is a recognised contributor to the emergence of resistance. Improved farm management practices and antibiotic alternatives, such as probiotics and phage therapy, are recommended to limit disease spread and resistance selection.

International trade and spread of resistance

There is emerging evidence that international food trade facilitates the movement of resistant bacteria and genes across regions. While food trade is a driver of dissemination, its importance remains difficult to quantify. Epidemiological analysis of resistance patterns in relation to trade routes is recommended to provide further insights.

Legislations on antimicrobial resistance with influence on trade

There are no trade restrictions specific to antimicrobial resistance, and existing measures vary by country. The Codex Alimentarius guides regulation voluntarily but lacks explicit provisions addressing this issue. Establishing standards on acceptable levels of resistant bacteria in food remains difficult due to insufficient data on human health impacts.

Conclusion and future directions

Quantifying the burden in food remains challenging due to variable transmission estimates. Effective antimicrobial stewardship, including reductions in use of up to 80%, is recommended. Enhanced biosecurity, international collaboration, and comprehensive risk analysis are essential to safeguard food safety, animal health, and the integrity of global trade.