Zeroing in on food safety tests — are they too sensitive?

Ultra-sensitive food safety tests may drive food waste, excessive packaging and unavailability with limited public health benefit, according to a Frontiers in Science study.

The international team of researchers make it clear that food safety is an important concern, as foodborne pathogens account for approximately 420,000 deaths and 600 million cases of illness each year. However, the authors argue that food systems will be more sustainable, while continuing to protect public health, if ‘zero-detection’ expectations are replaced with evidence-based targets for ‘sufficiently safe’ food.

The article sets out how regulators might find trade-offs with other important factors, such as food supply security, sustainability and nutritional health.

“Although the public expects food to be completely safe, there will always be some risk of foodborne illness. Zero risk doesn’t exist, and we shouldn’t be aiming for that either. Just as we don’t limit highway speeds to 10 miles per hour to minimise road deaths, we need to take a balanced approach that considers possible negative consequences of extreme food safety measures,” said lead author Prof Martin Wiedmann from Cornell University.

Impact of aiming for zero risk

According to the study, many rules and purchasing standards rely heavily on detecting a pathogen, sometimes treating any detection as unacceptable without fully considering dose, exposure, the food’s ability to support microbial growth, or who is most at risk.

Throwing away such food reduces the available food supply and wastes resources. Similarly, recalling food products from consumers can damage consumer trust, pushing people away from otherwise healthy products.

The authors argue that other protective measures, such as storage temperatures, packaging and heat treatment, can waste energy, increase costs and reduce nutritional content. While these are all important safety measures, they should only be applied if needed and associated trade-offs should be considered.

“A tremendous amount of food is wasted that would have been sufficiently safe to eat. Too often, trade-offs such as environmental or economic costs are only considered after a traditional microbial risk assessment. We cannot afford to carry on like this at a time when we desperately need to reduce our impact on the planet and assure not only food safety but food security,” said co-author Prof Sophia Johler at Ludwig Maximilian University of Munich, Germany.

Focus on risk rather than hazard

The current situation is driven by an emphasis on hazard-based assessments, according to the authors, where regulations focus on detecting pathogens, regardless of the threat to consumers. The researchers argue that the food system should move towards more flexible risk-based approaches, which assess the probabilities of harms and adjust the safety measures accordingly.

Regulations that overemphasise stringent corrective actions (such as recalls) when swab samples from a food-processing facility test positive for an indicator, for example, could lead to undue corrective actions in areas that are unlikely to contaminate the food. The authors explain that this could be an opportunity cost that diverts resources away from more effective interventions and control strategies in high-risk areas.

“There’s well-established evidence that focusing on end-product testing is generally ineffective to ensure safety. Overemphasis on end-product testing may distract from other food safety measures (eg, applying validated and verified process controls), which can provide greater public health benefits,” said co-author Dr Sriya Sunil at Cornell University.

Better tools to assess priorities

Computational tools that incorporate vast amounts of information across the food production system could help with establishing acceptable risks.

One challenge is how to prioritise different hazards. For example, in the US, norovirus causes thousands of times more cases than Listeria monocytogenes, yet Listeria monocytogenes causes more deaths per year.

While there are trade advantages to having consistent international food safety standards, the balance between competing interests may vary between regions. This can become even more complex when factoring in the health and environmental implications of greenhouse gas emissions.

“Specialists across social sciences, economics and life sciences must work together to establish values that align with consumers’ priorities. Together with advanced models that build on geographic information, AI and genomics, we can assess, manage and communicate risks far more accurately,” Wiedmann said.

Image credit: iStock.com/Blueastro