Spoilage microbe survival in long-life chilled foods

New member subscription-funded research is uncovering significant data regarding spoilage organisms survival in long-life chilled foods. Historically, chilled foods have been processed at 90°C/10mins (long life) or 70°/2mins (short life) to achieve microbiological safety. This has targeted the inactivation of 2 specific food pathogens: C. botulinum and L.monocytogenes respectively. There is limited advice available on the effects of these processes on spoilage organisms and subsequent shelf-life of long-life chilled foods. A literature review revealed a number of spore-forming Bacillus and Clostridium species that could survive 90°C/10mins treatment and grow in long-life foods. In particular, several Bacillus species could survive and grow at chill temperatures after such processes.

Experimental work showed that some heat treatments, considered to be equivalent to 90°C/10mins for C. botulinum, did not give the same level of reduction of Bacillus spores.

Further work

Further work is now being done to look at the interactions of other factors such as pH and Aw with these 'equivalent' heating temperatures on the potential for growth of heated 'non-target' organisms (i.e. non C. botulinum) in chilled foods. Manufacturers of these foods should consider challenge testing or predictive modelling to evaluate the risks from these organisms in their food formulations.

Contact: Gail Betts
+44(0)1386 842071
gail.betts@campdenbri.co.uk