Category Archives: Bacillus cereus

RASFF Alert – Bacillus cereus- Dairy Dessert

kswfoodworld food safety poisoning

RASFF-Bacillus cereus (4500 CFU/ml) in dairy dessert from France in France

Research -Bacteria isolated from the bovine gelatin production line: biofilm formation and use of different sanitation procedures to eliminate the biofilms

Wiley Online


The objective of this study was to evaluate the biofilm formation by Staphylococcus aureus, Bacillus cereus, and Bacillus licheniformis, as well to verify the efficiency of the sanitation procedures (cleaning, disinfection, and cleaning + disinfection) on the biofilm removal. Biofilms were formed after immersion of stainless steel and PVC coupons into different culture media (semi‐finished bovine gelatin, final gelatin, and hydrolyzed collagen) at 35°C for 5, 32, and 48 hr. After 32 hr of contact, all microorganisms were capable to form biofilms on the different surfaces in contact with all culture media tested. The semi‐finished gelatin and the hydrolyzed collagen provided a higher biofilm formation (counts between 3.54 and 7.87 log CFU/cm2) when compared to the final gelatin (counts between 3.05 and 6.70 log CFU/cm2). The cleaning step complemented with the disinfection with peracetic acid was the only procedure capable of removing all biofilms (counts ❤ log CFU/cm2).

Practical applications

In this study, we investigated the biofilm formation by different isolates from bovine gelatin, simulating the processing conditions of gelatin and hydrolyzed collagen. The present study showed a peculiar result since the gelatin was the culture medium that provided a lower biofilm formation, while the hydrolyzed collagen and the semi‐finished gelatin provided the best conditions for the formation of biofilms. In addition, we verified that the use of detergent or disinfectant alone was not efficient in the removal of the biofilms formed. In view of this, we suggest the requirements to prevent the formation of microbial biofilms of different bacterial species in the gelatin processing industry. In addition, we suggest measures to remove the biofilms from food processing surfaces.

Research – Kitchen Towel As Risk Factor for Home Based Food Poisoning

Abstracts Online

Background: Cross contamination in the kitchen could contribute to home-based food poisoning. This study aimed at investigating the potential role of kitchen towels in cross contamination in the kitchen. Methods: A total of 100 kitchen towels were collected after one month of use. The bacteria were cultured and identified by standard biochemical tests. A questionnaire was also designed to investigate the potential risk factors which could affect the result. Results:  Bacterial growth was found in 49% of the kitchen towels and significantly increased by size of family, extended family and presence on children. Multipurpose towels had higher CFU than single use towels (1.31 x 107 vs 6.60 x 104; p<0.05) and humid towels had higher CFU than dry ones (4.8 x 105 vs 0.5x 105; p<0.05). The mean CFU from the towels was found to be 2.76 x 105 and was significantly higher from the cotton towels (4.98 x 105) compared to the nylon (1.64 x 105) and mixture of both towels (1.89 x 105). Out of the 49 samples which were positive for bacterial growth, 36.7% grew coliforms, 36.7% Enterococcus spp., 30.6% Pseudomonas spp., 28.6% grew Bacillus spp., 14.3% S. aureus, 4.1% Proteus spp., 2.0% coagulase negative Staphylococcus. Furthermore, S. aureus was isolated at higher rate from families of lower socio-economic status (p<0.05) and those with children (p<0.05). The risk of having coliforms was twice on humid towels than the dried ones. It was also noted that as the CFU increased, the detection rate of coliform, Enterococcus spp., Proteus spp. and Bacillus spp. also increased significantly. Furthermore, Enterococcus spp. and S. aureus were isolated at higher prevalence in bigger families (p<0.05). Diet was also found to be an important factor. Coliform and S. aureus were detected at significantly higher prevalence from families on non-vegetarian diets while a higher prevalence of Enterococcus species from the kitchen towels of vegetarian families. Conclusions: This study conclude that kitchen towels could be very important source bacterial contamination which could contribute to food poisoning. The multipurpose usage of kitchen towels should be discouraged.

Hong Kong – Packed milk drink sample found to contain excessive Bacillus cereus


Issue Date 8.6.2018
Source of Information Centre for Food Safety
Food Product Skimmed Hi-Calcium Milk Drink
Product Name and Description Product name: Skimmed Hi-Calcium Milk Drink

Manufacturer: Nestlé Hong Kong Limited

Volume: 236 millilitre per pack

Use-by date: June 2, 2018

Reason For Issuing Alert
  • The Centre for Food Safety (CFS) collected the concerned sample from a supermarket in Kwun Tong for testing under its routine Food Surveillance Programme. The test result showed that the sample contained Bacillus cereus at a level of 4 600 000 per gram. Under the Microbiological Guidelines for Food, if ready-to-eat food contains Bacillus cereus at a level of more than 100 000 per gram, it is considered unsatisfactory.
Action Taken by the Centre for Food Safety
  • The CFS had informed the manufacturer and the vendor concerned of the test result. Investigation was conducted at the production plant and the supermarket concerned and follow-up samples were collected for further testing. Investigation is ongoing.
  • The CFS had also provided health education on food safety and hygiene for the staff of the production plant and the supermarket and requested them to carry out thorough cleaning and disinfection.
  • The CFS will alert the trade, continue to follow up on the incident and take appropriate action in order to safeguard public health and food safety.
Advice to the Trade
  • According to Section 54 of the Public Health and Municipal Services Ordinance (Cap 132), all food available for sale in Hong Kong, locally produced or imported, should be fit for human consumption. An offender is subject to a maximum fine of $50,000 and imprisonment for six months upon conviction.
Advice to Consumers
  • Bacillus cereus is commonly found in the environment. Unhygienic conditions in food processing and storage may give rise to its growth. Consuming food contaminated with excessive Bacillus cereus may cause gastrointestinal upset such as vomiting and diarrhoea.
Further Information The CFS press release


Research – Effect of Electrolyzed Water on the Disinfection of Bacillus cereus Biofilms: The Mechanism of Enhanced Resistance of Sessile Cells in the Biofilm Matrix

Journal of Food Protection

This study examined the disinfection efficacy and mechanism of electrolyzed water (EW) on Bacillus cereus biofilms. B. cereus strains, ATCC 14579 and Korean Collection for Type Cultures (KCTC) 13153 biofilms, were formed on stainless steel (SS) and plastic slide (PS) coupons. Mature biofilms were treated with slightly acidic EW (SAEW), acidic EW (AEW), and basic EW (BEW). SAEW (available chlorine concentration, 25 ± 1.31 mg L−1; pH 5.71 ± 0.16; and oxidation reduction potential, 818 to 855 mV) reduced ATCC 14579 biofilms on plastic slides to below the detection limit within 30 s. However, biofilms on SS coupons showed a higher resistance to the SAEW treatment. When the disinfection activities of three types of EW on biofilms were compared, AEW showed a higher bactericidal activity, followed by SAEW and BEW. In contrast, BEW showed a significantly (P < 0.05) higher biofilm dispersal activity than AEW and SAEW. SAEW disinfection of the B. cereus biofilms was due to the disruption of the B. cereus plasma membrane. The higher resistance of biofilms formed on the SS coupon might be due to the higher number of attached cells and extracellular polymeric substances formation that reacts with the active chlorine ions, such as hypochlorous acid and hypochlorite ion of SAEW, which decreased the disinfection efficacy of SAEW. This study showed that the EW treatment effectively disinfected B. cereus biofilms, providing insight into the potential use of EW in the food processing industry to control the biofilm formation of B. cereus.


RASFF Alert – Bacillus cereus – Spice Mix

kswfoodworld food safety poisoning

RASFF-Bacillus cereus (15000 CFU/g) and unauthorised colour auramine O in spice mix from Bangladesh in Finland

RASFF Alert – Bacillus cereus – Spice Mix

kswfoodworld food safety poisoning

RASFF-Bacillus cereus (14000 CFU/g) and unauthorised colour auramine O in spice mix from Bangladesh in Finland