Bacillus Cereus Contamination Research Articles

Reuterin formed by poultry-derived Limosilactobacillus reuteri HLRE05 inhibits the growth of enterotoxigenic Bacillus cereus in in vitro and fermented milk

The problem of food safety caused by Bacillus cereus contamination has been widely concerned, particularly in milk and its products, while effective prevention and control measures have not been implemented. Reuterin is a special broad-spectrum antibacterial substance produced by Limosilactobacillus reuteri via glycerol fermentation and is considered as a viable alternative to preservatives. In this study, a health poultry-derived L. reuteri HLRE05 (lineage VI strain in the evolutionary branch) was used to confirm its ability to produce reuterin, and then its basic biological activity and inhibitory capacity against foodborne pathogens were evaluated by glycerol fermentation in in vitro and fermented milk. Results showed that L. reuteri HLRE05 exhibited high resistance to hydrogen peroxide and intestinal fluids, and its adhesion rate to intestinal epithelial cells (Caco-2) reached about 80%. The content of reuterin produced by glycerol fermentation in vitro reached to 9.98 mg/mL, and the addition of glycerol to the fermentation broth could significantly improve the ability of supernatant to inhibit common foodborne pathogens. In addition, reuterin inhibited enterotoxigenic B. cereus HN001 with concentration dependent manner and restricted its adhesion rate to intestinal epithelial cells. Furthermore, L. reuteri HLRE05 produced reuterin during milk fermentation and eradicated B. cereus HN001 in a short period of time. This study highlights the potential application of natural-sourced antimicrobial approach with specific L. reuteri HLRE05 to control the safety of dairy products.

Evaluation of the ability to detect Bacillus cereus in food of chromogenic agar media RAPID’B.cereus according to ISO 7932:2004

In this study, the ability to detect Bacillus cereus of the new chromogenic agar media RAPID’B.cereus (RBC) was compared with the standard selective culture media Mannitol Egg Yolk Polymyxin (MYP) recommended by food authorities for isolation, identification, and quantification of Bacillus cereus. Two types of media were used to conduct the assessment on five categories of food, including cereals and cereal products; flour and starch; vegetables and vegetable products; milk and dairy products; and confectionery (n = 164). The results of the survey Bacillus cereus contamination on RBC (75.61%), MYP (70.12%), of which 46.09% of the samples didn’t meet the standards of the Ministry of Health on the maximum allowable limit of Bacillus cereus in food. Conducting performance testing of RBC according to ISO 16140-2:2016 with parameters: growth, selectivity, specificity, relative trueness and accuracy profile, the analysis results all met the criteria according to the standard: the development (PR) of the two media were 0.97 and 0.81 respectively; a high level of background microflora was present on the MYP plates while if it was not the case on the RBC plates; both media allowed the detection of Bacillus cereus with a difference of 0.14.  Compared with the acceptance criteria as prescribed, the categories used in the study were all suitable for assessment in the new media with the accuracy between the two methods being equivalent.

New Operating Approach to Limit Bacillus Cereus Contamination of Donor Human Milk.

New Operating Approach to Limit Bacillus Cereus Contamination of Donor Human Milk.

Bacillus cereus contamination of pasteurized human milk donations: frequency, origin, seasonal distribution, molecular typing of strains and proposed corrective/preventive actions

Objectives An increase in pasteurized human milk contamination with Bacillus cereus was witnessed in milk donated to the Amiens-Picardie Human Milk Bank over the 2017–2018 period. To better understand the origin of such an increase, this study aimed to describe the frequency of Bacillus cereus contamination in anonymous and personalized human milk donations of Amiens Human Milk Bank in 2018, compare the genetic profiles of Bacillus cereus strains found in pasteurized human milk and set up corrective/preventive actions to reduce Bacillus cereus contamination. Study design A retrospective cohort study of human milk donated from January to December 2018 was set. Data on the microbiological quality of donated human milk and genetic profiles of Bacillus cereus strains isolated from pasteurized donated human milk and the environment were collected. Results The overall noncompliance rate related to the microbiological quality in the 1585 batches of analyzed human milk donations was of 27.3%. Post-Holder pasteurization, rejection rates were significantly higher for anonymous donations as compared to personalized ones. Bacillus cereus was the main cause of noncompliance. Bacillus cereus contaminations could not be attributed to a single strain spreading through Amiens human milk bank and Amiens hospital environment as the genetic profiles of the collected strains were different. Corrective actions led to a decrease in the noncompliance rate due to Bacillus cereus (37.7–9.7%) post-Holder pasteurization. Conclusion Bacillus cereus was the primary cause of rejection for pasteurized human milk donations over the investigated period. These contaminations did not originate from the spread of a single strain. A first round of corrective actions enabled a fair decrease in Bacillus cereus contaminations.

Contamination of Bacillus cereus in Elementary School Snack Food

Many food snacks have the advantage but still have health risks as evidenced by the many cases of food poisoning, one of the causes of food poisoning is Bacillus cereus. This study aims to determine the amount and percentage of Bacillus cereus pollution on snacks sold in elementary schools. This research is expected to provide information to the public about the presence or absence of bacteria Bacillus cereus contamination. This research uses purposive sampling technique. The sample used in this study was hawker food sold in Elementary School as many as 20 samples consisting of 10 samples that have not fried and ten samples that have cooked. The results of the questionnaire study showed 83% of sellers did not put snacks in closed containers and found Bacillus cereus in meals. Conclusion 9 (45%) of food samples contaminated with Bacillus cereus bacteria

Removal of B. cereus cereulide toxin from monoclonal antibody bioprocess feed via two-step Protein A affinity and multimodal chromatography

A rapid and sensitive liquid chromatography-mass spectrometry assay was developed and used to quantify emetic cereulide peptide exotoxin, which can be related to possible Bacillus cereus contamination in monoclonal antibody (mAb) bioprocess feeds. The assay limit of detection was 0.05 ng/mL (~1 fmol injected) and limit of quantification 0.16 ng/mL (~3 fmol injected) over a standard curve with >3 orders of magnitude linear dynamic range. The assay allowed quantification of toxin removal in an established two-step mAb purification process consisting of Protein A affinity chromatography followed by multi-modal anion exchange chromatography. Toxin content was ascertained in process stream sample fractions as well as on the Protein A affinity column. An optimized analytical method allowed separation of cereulide toxin from other mAb cell culture components within 6 min. Spiking experiments showed that samples should be collected in high (80% v/v) content acetonitrile to reduce nonspecific losses of the cereulide. The majority of mAb purification process-associated cereulide was detected in the Protein A flow through fraction, whereas only residual amounts were found in wash, strip, and elution fractions. Column cleaning-in-place (CIP) procedures were evaluated to prevent carryover between affinity capture cycles. No carryover was detected between cycles, however trace amounts of cereulide were extracted from the Protein A resin. Increasing the CIP NaOH concentration from 0.1 M to 0.5 M, and contact time from 15 min to 1 h, improved removal of residual cereulide from the resin. Applicability of CIP clearance of cereulide during Protein A chromatography was confirmed with three different mAb feeds. Post Protein A polishing, via target flow through on a multi-modal anion exchange chromatography column, resulted in a product pool with no detectable cereulide. Approximately 5 logs of reduction in cereulide concentration was obtained over the two-step chromatography process. Cereulide contamination is well known and of concern in food processing, however this research may be the first LC-MS quantification of cereulide contamination, and its clearance, in biopharmaceutical mAb processing. The analytical method may also be used to rapidly screen for cereulide contamination in upstream cell culture process streams, prior to downstream product purification. This will allow appropriate measures to be taken to reduce toxin exposure to downstream bioprocess raw materials, consumables and equipment.

Microbial quality of reduced-sodium napa cabbage kimchi and its processing.

This study evaluated the microbial safety of reduced‐sodium napa cabbage kimchi products by comparing with conventional kimchi samples. Five commercial kimchi samples were collected from different manufacturers in Korea. Total aerobic plate counts and coliforms counts between regular and reduced‐sodium kimchi were not significantly (p > 0.05) different and major foodborne pathogens, including Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, and Yersinia enterocolitica were not detected in any sample. Bacillus cereus contamination among all kimchi samples was less than the regulation level (3.0 log CFU/g). However, high levels of coliforms were observed in both types of samples. To investigate microbial hazards of kimchi processing, we analyzed specific kimchi production processes and found five control points which can reduce coliform levels in kimchi samples. The results of this study could be helpful for the kimchi industry to produce safe reduced‐sodium kimchi products.

Monitoring of Sulfur Dioxide, Carotenoid Contents and Bacillus cereus Contamination of Dried Sweet Potato in Circulating Dried Agricultural Products

Monitoring of Sulfur Dioxide, Carotenoid Contents and Bacillus cereus Contamination of Dried Sweet Potato in Circulating Dried Agricultural Products

Proposal of statistical sampling plans for Bacillus cereus in Korean fermented soybean pastes

Bacillus cereus contamination is one of the major problems for food safety in Korean fermented soybean pastes. A one-sample inspection is not sufficient to determine the overall level of contamination. The aims of this study were to propose new statistical sampling plans for B. cereus in Korean fermented soybean pastes. The acceptable probability over 95% is considered suitable for sampling plan. We suggest statistical sampling plans for B. cereus A (n=5, c=2, m=3, and M=4), B (n=5, c=0, and m=4), or C (n=5, c=1, m=4, and M=5) in Korean fermented soybean pastes based on the B. cereus standard in current Korean Food Code and the median and mean value from the 150 pastes estimated in this study. The statistical sampling plans for B. cereus proposed in this study will provide an advanced food regulation and permit harmonization with international food standards.

Prevalence, genetic diversity, and antibiotic resistance of Bacillus cereus isolated from Korean fermented soybean products.

Bacillus cereus contamination is a major food safety problem for Korean fermented soybean products, but few studies have assessed its potential to cause foodborne illness. The objectives of this study were to investigate the prevalence and characteristics of B. cereus isolated from Korean fermented soybean products. B. cereus was detected in 110 of 162 (67.9%) samples. The highest B. cereus frequency was observed in deonjang (68 of 93 samples, 73.1%) and cheonggukjang (18 of 25, 72.0%); however, nonhemolytic enterotoxin was detected only in 22 of 162 samples (13.6%). Although the tested B. cereus isolates showed diverse pulsotypes according to repetitive sequence-PCR banding patterns, they displayed similar antibiotic sensitivity spectra. The low frequency of enterotoxin detection suggests that the potential risk of B. cereus foodborne illness associated with Korean fermented soybean products is lower than generally presumed. However, considering the prevalence of B. cereus and the high content of fermented soybean products in the Korean diet, it is necessary to constantly monitor the level of contamination with B. cereus and its toxins in such Korean food products.

Possible contamination of organ preservation fluid with Bacillus cereus: the United Kingdom response

We describe here the United Kingdom (UK) response following the recent international recall of an organ preservation fluid owing to potential Bacillus cereus contamination. This fluid is used for the transport of solid organs and pancreatic islet cells for transplant. We detail the response mechanisms, including the initial risk stratification, investigatory approaches, isolate analysis and communications to professional bodies. This report further lays out the potential need for enhanced surveillance in UK transplant patients.

Safety assessment of recalled Haemophilus influenzae type b (Hib) conjugate vaccines—United States, 2007–2008

On 13 December 2007, Merck & Co., Inc. voluntarily recalled 1.2 million doses of Haemophilus influenzae type b (Hib) vaccines that had been distributed since April 2007 for concerns regarding potential Bacillus cereus contamination. Enhanced postrecall surveillance was conducted to detect vaccine-associated B. cereus infections. We reviewed reports involving recalled Hib vaccines received by the Vaccine Adverse Event Reporting System (VAERS) during 1 April 2007-29 February 2008. For each reported death, autopsy review sought evidence of B. cereus infections. For each specified outcome, the proportional reporting ratios (PRRs) were calculated to compare the recalled Hib vaccines with the manufacturer's nonrecalled Hib vaccines in the VAERS databases. On 20 December 2007, we used the Epidemic Information Exchange (Epi-X) to solicit nongastrointestinal vaccine-associated B. cereus infections, and requested B. cereus isolates for genotyping to compare with the manufacturing facility isolate. VAERS received 75 reports involving recalled Hib vaccines; none described a confirmed B. cereus infection. Comparative analyses did not reveal disproportionate reporting of specified outcomes for recalled Hib vaccines. The Epi-X posting triggered one report of vaccine-associated B. cereus bacteremia from a child who received a nonrecalled Hib vaccine manufactured by Merck; the genotypes of isolates from the patient and the manufacturing facility differed. No evidence of vaccine-associated B. cereus infection had been found in recipients of recalled Hib vaccines. Conducting laboratory surveillance through Epi-X was feasible and may enhance public health response capacities for future vaccine safety emergencies.

Reduction of Bacillus cereus Contamination in Biofilms on Stainless Steel Surfaces by Application of Sanitizers and Commercial Detergent

We established the effectiveness of a washing, detergent and sanitizer treatments for reducing Bacillus cereus (B. cereus) contamination in biofilms on stainless steel surfaces. A water treatment did not affect biofilms and chlorine treatments at 200 ppm for 10 min and 300 ppm for 5 min, iodophor at 200 ppm for 10 min, and QAC at 400 ppm for 10 min were used to eliminate all B. cereus cells. B. Cereus cells after detergent treatment were eliminated by chlorine at 100 ppm for 10 min, 200 ppm for 5 min, and 300 ppm for 3 min, and with iodophor at 100 ppm for 10 min and 200 ppm for 10 min, and QAC at 400 ppm for 10 min.

病院タオルの<i>Bacillus cereus</i>汚染を測定する方法の比較検討

病院で使用するタオルには，加熱処理が義務づけられている．しかし，熱に耐性であるBacillus cereusの芽胞が病院タオルを汚染することがある．さらに，病院タオルのB. cereus汚染は医療関連感染の原因となりうる．したがって，病院タオルのB. cereus汚染を定期的に評価する必要がある．しかし，その評価のための標準方法は確立されていない．今回の研究において，我々は4つの測定方法(スタンプ法・スワブ法・単純抽出法・ビーズ抽出法)を用いて，病院タオルのB. cereus汚染の評価を行なった．スタンプ法ではタオル汚染を定量評価することが不可能であった．また，スワブ法では病院タオルから少数のB. cereusしか検出できなかった．一方，抽出法では病院タオルから多数のB. cereusを検出することができた．特に，ビーズ抽出法では単純抽出法の2倍の菌数を検出することができた．以上の結果より，ビーズ抽出法は病院タオルのB. cereus汚染の評価に最も適した測定方法と考えられる．さらに本研究の結果から，タオル中のB. cereusの分布密度が不均一であることが判明した．したがって，タオルのB. cereus汚染を評価する場合，1枚のタオルから複数のサンプル断片を採取して調べる必要がある．

Contamination of milk with Bacillus cereus by post-pasteurization surface exposure as evaluated by automated ribotyping

Over the last decade, increased transportation of refrigerated raw milk from farms to factories has raised concerns over Bacillus cereus contamination in the Brazilian dairy industry. Twelve isolates from pasteurized milk and 30 isolates from the post-pasteurization equipment surfaces of a dairy processing unit were characterized as B. cereus. Seven ribotypes were identified, demonstrating the genetic variability of this microorganism. Most of the isolates belonged to the same ribogroup (RIBO1222-73-S4), and they were found on four surfaces and also in the milk, indicating the role of the equipment surfaces as reservoirs for milk recontamination.

Prevalence and characterisation of Bacillus cereus in vacuum packed potato puree

SummaryRefrigerated processed foods of extended durability (REPFED) potato puree was analysed for Bacillus cereus contamination along the production line and during the product shelf‐life. Isolated B. cereus strains were tested for their psychrotrophic character and the ability to produce enterotoxins. Bacillus cereus contamination during four subsequent productions was in the range of 2.3–4.0 log cfu g−1. Productions five and six were significantly less contaminated with B. cereus (≤1 log cfu g −1). All B. cereus isolates from the first four productions were able to grow at 7 ° and 10 °C, whereas the majority of the isolates from productions five and six did not. No B. cereus isolates grew at 4 °C. randomly amplified polymorphic DNA (RAPD) fingerprinting showed that the most of B. cereus contamination originated from one source. In total, 30.4% of isolates expressed enterotoxic character. The present study points out the necessity to prevent an ‘in house’ colonisation and contamination during food processing in order to accomplish the safety of REPFED throughout the shelf‐life. It also indicates the most critical steps in the production line of ready‐to‐eat potato puree and impact of failures regarding the food safety. The data provided can be used for risk assessment studies regarding B. cereus in REPFED.

Characterization of Bacillus cereus isolates from fresh vegetables and refrigerated minimally processed foods by biochemical and physiological tests

Bacillus cereus contamination has been evaluated in a total of 56 samples of fresh peppers, cucumbers, tomatoes, carrots, zucchini, garlic and onions, used commonly as ingredients to manufacture refrigerated minimally processed foods. It has been also evaluated in some of these products, such as gazpacho (Mediterranean vegetable cold soup made from fresh vegetables), salmorejo (vegetable cold purée containing bread and egg), ajoblanco (cold cream containing bread, almond, and olive oil as main ingredients) and zanaranja (carrot and orange juice mixture). The average counts did not exceed 10 4 cfu g −1 in any case and all the vegetables and processed products except garlic and zanaranja presented contamination of this foodborne pathogen. Cucumbers presented the highest count among all the vegetable products analysed, followed by carrots. According to the ISO 7932:1993(F) confirmation procedure, a total of 36 presumptive B. cereus strains were isolated from the 85 samples of various vegetable products analysed. Isolates were further characterized and identified by API 50CH/20E phenotypic system using APILAB Plus software, combined with additional tests of motility, oxidase activity and anaerobic growth. Of the 36 presumptive B. cereus isolates, 32 (88·9%) were confirmed to be B. cereus, two strains (5·5%) were identified as B. licheniformis, and other two strains (5·5%) were identified as B. firmus. About 81·3% (26 strains) of 32 B. cereus tested isolates hydrolysed starch and 71·9% (23 strains) produced diarrheal enterotoxin in TSB culture as detected by the BCET-RPLA test. The heat resistance at 90°C for spores of the 32 B. cereus strains ranged from 1·4 to 21·2 min. Strains unable to hydrolyse starch were the most heat-resistant, with D 90 values higher than 10·8 min. All the enterotoxin-positive strains were able to hydrolyse starch.

Occurrence and survival of enterotoxigenic Bacillus cereus in some Nigerian flour-based foods

Flours that form the staple foods of Nigerians were sampled from the market to assay for Bacillus cereus contamination and the ability of the toxigenic strain to survive their normal cooking temperatures. Out of a total of 300 samples collected, five (2.0%) were without detectable levels of B. cereus, 84 (28.0%) were present at 1 × 10 3 cells/g; 194 (64.7%) were present at 1 × 10 4 cells/g and 22(7.3%) at 1 × 10 5 cells/g. All the samples were equally contaminated with high levels of bacteria. Of the 72 isolates tested for enterotoxin production, 33 (45.8%) were toxigenic by the ileal loop test. One of the toxigenic strains tested survived the preparation temperature of the ‘foo-foo’ and was able to initiate growth in the sample ‘tuwo’.