The work, which formed part of the Sustainable Shelf-Life Extension (SUSSLE) project, has provided new distribution information about the background levels of C.botulinum spores in a range of raw ingredients.
The findings will reduce experimental uncertainty about the risks involved by generating higher quality data for better risk assessments, which will raise confidence about the predicted shelf-life of different foodstuffs.
Botulism is a serious form of food poisoning, caused by a deadly neurotoxin produced by C.botulinum. While rare, outbreaks have occurred and one such example occurred in Ohio in the US last year. This resulted from potato salad made with unsafe ‘home-canned’ potatoes which contained C.botulinum.
Consumer demand for reduced preservatives, milder heat processing and longer shelf-lives, is driving continuous innovation in minimally processed chilled foods. But delivering this needs a full understanding of how these changes affect the growth of bacteria, such as C.botulinum.
Professor Mike Peck and Dr Gary Barker from IFR’s Gut Health and Food Safety Programme have played a key part in the SUSSLE project. Its results will not be made available to non-project partners until January 2018.
In the SUSSLE project, IFR collaborated with the Chilled Food Association and Unilever Research to enhance the sustainability of minimally processed chilled foods by using quantitative risk assessment to set a safe shelf-life with respect to C.botulinum, and reduce energy usage for minimally processed chilled foods.
As part of the research, Peck and his team discovered that much lower C.botulinum spore concentrations in food than those originally thought could lead to germination and cause botulism.
Through experimentation, they found that concentrations peaking between 1–10 spores/kg, rather than 10–100 spores/kg previously reported in the literature, were sufficient to cause germination.
“The evidence shows that for many raw food materials, typical spore loads are smaller than previously reported,” said Peck. “This makes a big difference to how we make decisions about food safety and risk assessment.
“We now believe the peak is between 1–10 spores/kg and, importantly, the distribution is not as wide – the shape of the curve is more pointy.”