Tag Archives: food contamination

Research – Bacillus cereus – Sporulation of Bacillus spp. within biofilms – Effect of Temperatures on the Growth, Toxin Production, and Heat Resistance of Bacillus cereus in Cooked Rice

Science Direct

Bacillus strains are often isolated from biofilms in the food industries. Previous works have demonstrated that sporulation could occur in biofilms, suggesting that biofilms would be a significant source of food contamination with spores. In this study, we investigated the properties of mono-species and mixed Bacillus biofilms and the ability of Bacillus strains to sporulate inside biofilms. Bacillus strains were able to form mono-species biofilms on stainless steel coupons, with up to 90% spores after a 48 h-incubation. These spores were highly resistant to cleaning but were easily transferred to agar, mimicking the cross-contamination of food, thereby suggesting that biofilms would be of particular concern due to a potential for Bacillus spore food contamination. This hypothesis was strengthened by the fact that Bacillus strains were able to form mixed biofilms with resident strains and that sporulation still occurred easily in these complex structures.

Mary Ann Leibert

Bacillus cereus is capable of producing enterotoxin and emetic toxin, and Bacillus foodborne illnesses occur due to the consumption of food contaminated with endospores. The objectives of this study were to investigate the growth and toxin production of B. cereus in cooked rice and to determine the effect of temperature on toxin destruction. Cooked rice inoculated with B. cereus was stored at 15, 25, 35, and 45°C or treated at 80, 90, and 100°C. The results indicated that emetic toxin was produced faster than enterotoxin (which was not detected below 15°C) at all the storage temperatures (15–45°C) during the first 72 h. Emetic toxin persisted at 100°C for 2 h, although enterotoxin was easily to be destroyed by this treatment within 15 min. In addition, B. cereus in cooked rice stored at a warm temperature for a period was not inactivated due to survival of the thermostable endospores. These data indicate that the contaminated cooked rice with B. cereus might present a potential risk to consumers. Results from this study may help enhance the safety of such food, and provide valuable and reliable information for risk assessment and management, associated with the problem of B. cereus in cooked rice.

Research Salmonella Biofilm Resistance

ASMOrg Salmonella

Salmonellosis is the second most common cause of food-borne illness worldwide. Contamination of surfaces in food processing environments may result in biofilm formation with a risk of food contamination. Effective decontamination of biofilm contaminated surfaces is challenging. Using the CDC biofilm reactor, the activity of sodium hypochlorite, sodium hydroxide and benzalkonium chloride were examined against an early (48 hours) and relatively mature (168 hours) Salmonella biofilm. All 3 agents result in reduction in viable counts of Salmonella, however only sodium hydroxide resulted in eradication of the early biofilm. None of the agents achieved eradication of mature biofilm, even at 90-minutes contact time. Studies of activity of chemical disinfection against biofilm should include assessment of activity against mature biofilm. The difficulty of eradication of established Salmonella biofilm serves to emphasise the priority of preventing access of Salmonella to post-cook areas of food production facilities.

European Research – Listeria monocytogenes


Monitoring of food contamination by Listeria monocytogenes.

The national plan implemented by the DGCCRF is intended to monitor the contamination of food at the distribution stage. During these checks, investigators collected more than 3,600 samples

Of all the goods taken Listeria monocytogenes was found in 1.5% of cases. Only two cheeses have reached the prescribed limit (100 cfu / g) or 0.06% of the samples analysed. The analysis results indicate a low level of non-compliant products.

These results and the significant decrease in the number of establishments abnormality (38% in 2 years) shows the continuous improvement of the microbiological quality of food and hygiene conditions in the retail sector.

FSA – Norovirus Advice and Information


During the current norovirus outbreak, the FSA is reminding people what they can do when preparing food to minimise the likelihood of food contamination. Tackling foodborne norovirus is one of the priorities for the Agency, as part of its Foodborne Disease Strategy. (see link above)