Category Archives: Bacillus

Research – Decontamination of Bacillus cereus in cardamom (Elettaria cardamomum) seeds by infrared radiation and modeling of microbial inactivation through experimental models

Posted on November 16, 2019 by | Leave a comment

Wiley Online 

In this work, infrared (IR) irradiation was used for inactivation of Bacillus cereus in cardamom seeds. The effect of IR power (100, 200, and 300 W), sample distance from radiation source (5, 10, and 15 cm) and holding times (0–11 min) was investigated on B. cereus count, as well as cardamom seeds color and temperature profiles. Inactivation of B. cereus on cardamom seeds during IR processing was demonstrated by experimental models. The highest reduction of B. cereus count (5.11 Log CFU/g) was achieved after 8 min IR irradiation at 300 W power and 15 cm distance. Measurement of temperature profiles revealed that there was a significant difference (p < .05) between surface and center temperatures of the cardamom seeds. The green color (a* value) of cardamom seeds was slightly affected and the highest color change was observed at 200 W IR, 10 cm distance and 10 min irradiation that resulted in an increase of a* from −3.05 ± 0.96 to −0.05 ± 0.44. In conclusion, IR irradiation could be successful for decontamination of cardamom seeds without severe alteration of its quality. Among the experimental models for microbial inactivation during IR processing, the Double Weibull model had the highest coefficient value of determination (R2 = 0.9966).

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Posted in Bacillus, Bacillus cereus, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Technology, microbial contamination, Microbiology, Research, Technology, Uncategorized

RASFF Alert – Bacillus cereus – Chilled Milk

Posted on November 15, 2019 by | Leave a comment

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RASFF -Bacillus cereus (up to 700 CFU/g) in chilled milk from Germany in Germany

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Posted in Bacillus, Bacillus cereus, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology Blog, Food Pathogen, Food Poisoning, food recall, Food Safety, Food Safety Alert, Food Testing, Food Toxin, RASFF, Uncategorized

RASFF Alert – Bacillus cereus- Cinnamon and Curry

Posted on October 25, 2019 by | Leave a comment

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RASFF – enterotoxin producing Bacillus cereus (6000 and 120000 CFU/g) in cinnamon and curry from the West Bank and Gaza Strip in Slovenia

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Posted in Bacillus, Bacillus cereus, Enterotoxin, food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Poisoning, food recall, Food Safety, Food Safety Alert, Food Testing, Food Toxin, RASFF, Uncategorized

Research –

Posted on August 24, 2019 by | Leave a comment

Canadian Journal of Microbiology

 

ABSTRACT

Probiotics have become one of the potential solutions to global restriction on antibiotic use in food animal production. Bacillus species have been attractive probiotics partially due to their long-term stability during storage. In this study, 200 endospore-forming bacteria isolates were recovered from sourdough and the gastrointestinal tract (GIT) of young broiler chicks. Based on the production of a series of exoenzymes and survivability under stress conditions similar to those in the poultry GIT, 42 isolates were selected and identified by 16S rRNA gene sequencing. Seven strains with a profile of high enzymatic activities were further evaluated for sporulation efficiency, biofilm formation, compatibility among themselves (Bacillus spp.), and antagonistic effects against three bacteria pathogenic to poultry and humans: Enterococcus cecorum, Salmonella enterica, and Shiga-toxin-producing Escherichia coli. The strains from sourdough were identified as Bacillus amyloliquefaciens whereas the ones from the chicks’ GIT were Bacillus subtilis. These strains demonstrated remarkable potential as probiotics for poultry.

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Posted in Bacillus, Salmonella, Uncategorized

Research – Prevalence and Diversity of the Thermotolerant Bacterium Bacillus cytotoxicus among Dried Food Products

Posted on June 29, 2019 by | Leave a comment

Journal of Food Protection

ABSTRACT

Bacillus cytotoxicus, a member of the Bacillus cereus group, is a thermotolerant species originally reported from a lethal foodborne infection in France in 1998. The strain NVH391-98, isolated from this outbreak, produces cytotoxin K1, a potential cytotoxic enterotoxin. However, the habitat and diversity of B. cytotoxicus isolates so far have been poorly explored. The objective of this study was to assess the prevalence of this bacterium in different food products (mainly dried) and to estimate its diversity. Among the 210 samples analyzed, all potato flakes contained the bacterium at low concentrations (≤102 CFU/g). However, prepared and kept at room temperature for 2 days, the puree contained ca. 105 CFU/g B. cytotoxicus. Besides potato flakes, some samples of millet flour, salted potato chips, and soups also contained B. cytotoxicus. From these samples, 55 thermotolerant B. cytotoxicus isolates were obtained. When classified into six distinct random amplified polymorphism DNA patterns, they showed the existence of 11 distinct plasmid profiles. Although most isolates (including the reference strains NVH391-98 and NVH883-00) contained no detectable plasmid, some displayed one to three plasmids with sizes from ca. 8 to 90 kb. It also emerged from this study that a single food sample could contain B. cytotoxicus isolates with different genetic profiles.

HIGHLIGHTS

  • Bacillus cytotoxicus was found in all tested potato flakes but at loads lower than 102 CFU/g.

  • B. cytotoxicus was observed in other potato-containing products and in millet flour.

  • B. cytotoxicus isolates (n = 57) fell into six RAPD patterns and 11 plasmid profiles.

  • A large proportion of B. cytotoxicus isolates contained small and/or large plasmids.

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Posted in Bacillus, Bacillus cytotoxicus, food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, food recall, Food Safety, Food Safety Alert, Food Testing, Food Toxin, Uncategorized

USA – Occurrence of Foodborne Agents at Food Service Facilities in the Czech Republic

Posted on June 29, 2019 by | Leave a comment

Journal of Food Protection

ABSTRACT

The aim of this study was to investigate the occurrence of foodborne agents at food service facilities in the Czech Republic. The sampling, performed from April 2016 to November 2017, focused on the microbiological monitoring of the environment at the establishment (EFS; n = 298) and the hands of staff (HFS; n = 159). The analysis targeted the presence of the following bacteria: Escherichia coli (focusing on the presence of Shiga toxigenic E. coli), Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Salmonella spp., and Campylobacter spp. A swab method using sterile abrasive sponges was used to detect bacteria in EFS; a glove-juice method was used to monitor microbial contamination on HFS. The presence of E. coliwas confirmed in 11.8% of samples (12.4%, EFS; 10.7%, HFS; P = 0.650). The presence of Shiga toxigenic E. coli was not confirmed in the samples. B. cereus was detected most frequently, in 39.6% of all samples taken (44.6%, EFS; 30.2%, HFS; P= 0.003). S. aureus was detected in 17.9% of samples (17.4%, EFS; 18.9%, HFS; P = 0.703). Of S. aureus isolates, 58.5% were found to be positive for the presence of genes producing staphylococcal enterotoxins (70%, HFS; 52.0%, EFS). L. monocytogenes was detected in only one sample (0.2%; EFS). The presence of Salmonella spp. and Campylobacter spp. was not confirmed. The occurrence of B. cereus, S. aureus, and E. coli was dependent on the season of the year. B. cereus and S. aureus occurred less frequently in the summer months, although E. coli was recorded more frequently. B. cereus, S. aureus,and E. coli were detected in almost half of the tested samples. The relatively high percentage of B. cereus and S. aureusisolates from EFS corresponded with the model in the final European Food Safety Authority reports on the occurrence of foodborne disease outbreaks in the European Union. Managers of food service facilities should focus on reducing the occurrence of B. cereus and S. aureus.

HIGHLIGHTS

  • Contamination of food service facilities in the Czech Republic by foodborne agents was determined.

  • Bacillus cereus, Staphylococcus aureus, and Escherichia coli were detected in almost 50% of samples.

  • The occurrence of B. cereus, S. aureus, and E. coli depended on the season of the year.

  • Regular monitoring of food service facilities for agents of foodborne disease is necessary.

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Posted in Bacillus, Bacillus cereus, E.coli, food bourne outbreak, food contamination, Food Hygiene, Food Illness, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Poisoning, food recall, Food Safety, Food Safety Alert, Food Testing, Listeria, Listeria monocytogenes, Shigatoxin, Staphylococcus aureus, STEC, Uncategorized

Research -Insights into Psychrotrophic Bacteria in Raw Milk: A Review

Posted on June 27, 2019 by | Leave a comment

Journal of Food Protection

ABSTRACT

Supply of high-quality dairy products is the goal of every dairy producer throughout the world. However, psychrotrophic bacteria in raw milk, generally comprising bacterial species of the genera Pseudomonas, Acinetobacter, Aeromonas, Serratia, Bacillus, Lactococcus, Microbacterium, and Staphylococcus, are of special concern to the dairy industry because they can produce heat-stable enzymes. These enzymes may withstand various heat treatments during dairy processing, causing quality defects over the product storage period. The levels and diversity of psychrotrophic bacteria in raw milk are tightly linked to natural habitats, milking practices, and hygiene practices of farms in different countries. Most psychrotrophic bacteria can form biofilms on various milk storage and processing equipment, which serve as persistent sources of microbial contamination due to their biotransfer potential. A comprehensive review of the diversity of psychrotrophic bacteria in raw milk, the spoilage potential of these bacteria, the specific technological problems caused by biofilms and heat-resistant enzymes, and potential strategies for controlling dairy spoilage starting at the farm level is needed for improving our understanding of these spoilage bacteria.

HIGHLIGHTS

  • Levels of psychrotrophic bacteria in raw milk are affected by to habitats and farm hygiene.

  • Biofilms formed by psychrotrophic bacteria are persistent sources of contamination.

  • Heat-stable enzymes produced by psychrotrophic bacteria compromise product quality.

  • Various strategies are available for controlling dairy spoilage caused by psychrotrophic bacteria.

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Posted in Bacillus, Biofilm, food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Poisoning, Food Safety, Food Spoilage, Food Testing, Pseudomonas, Uncategorized

Research -Study finds pathogen issues with ready-to-eat salad and sprouts

Posted on June 19, 2019 by | Leave a comment

Food Safety News

A study by German researchers has raised concerns on the microbiological quality of ready-to-eat salad mixes and fresh sprouts.

The three-year research project by the Max Rubner Institute also found the microbiological quality of cucumbers, carrots and mushrooms was good. Mixed lettuce received a good to medium result and herbs were rated as medium.

The focus was on Listeria, Salmonella, E. coli, Staphylococcus aureus and Bacillus cereus.

Researchers said the microbiological quality of ready-to-eat (RTE) mixed salads was “inadequate” as 7 of 116 samples, or 6 percent, were contaminated with human pathogenic bacteria. This figure was 2.5 percent for lettuce, 1.3 percent for carrots, 1.2 percent for mushrooms, 1.1 percent for sprouts and zero for herbs and cucumbers.

The team sampled a total of 600 products sold in northern and southern Germany including 115 samples of herbs, 40 cucumbers, 79 carrots, 80 types of lettuce, 116 RTE salads, 81 edible mushrooms, and 89 samples of sprouts in the project from 2015 to 2018.

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Posted in Bacillus, E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Listeria, Listeria monocytogenes, microbial contamination, Salmonella, Staphylococcus aureus, Uncategorized

RASFF Alerts – Bacillus cereus – Ginger Powder – Cardamom

Posted on June 14, 2019 by | Leave a comment

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RASFF – Bacillus cereus (>100000 CFU/g) in ginger powder from Spain in France

RASFF – Bacillus cereus (up to 53000 CFU/g) in cardamom from Lebanon in Austria

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Posted in Bacillus, Bacillus cereus, food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Poisoning, food recall, Food Safety, Food Safety Alert, Food Testing, Food Toxin, RASFF, Uncategorized

Research – Microbiological and real-time mechanical analysis of Bacillus licheniformis and Pseudomonas fluorescens dual-species biofilm

Posted on June 8, 2019 by | Leave a comment

Microbiology Research

n natural habitats, bacterial species often coexist in biofilms. They interact in synergetic or antagonistic ways and their interactions can influence the biofilm development and properties. Still, very little is known about how the coexistence of multiple organisms impact the multispecies biofilm properties. In this study, we examined the behaviour of a dual-species biofilm at the air–liquid interface composed by two environmental bacteria: Bacillus licheniformis and a phenazine mutant of Pseudomonas fluorescens . Study of the planktonic and biofilm growths for each species revealed that P. fluorescens grew faster than B. licheniformis and no bactericidal effect from P. fluorescens was detected, suggesting that the growth kinetics could be the main factor in the dual-species biofilm composition. To validate this hypothesis, the single- and dual-species biofilm were characterized by biomass quantification, microscopy and rheology. Bacterial counts and microscale architecture analysis showed that both bacterial populations coexist in the mature pellicle, with a dominance of P. fluorescens . Real-time measurement of the dual-species biofilms’ viscoelastic (i.e. mechanical) properties using interfacial rheology confirmed that P. fluorescens was the main contributor of the biofilm properties. Evaluation of the dual-species pellicle viscoelasticity at longer time revealed that the biofilm, after reaching a first equilibrium, created a stronger and more cohesive network. Interfacial rheology proves to be a unique quantitative technique, which combined with microscale imaging, contributes to the understanding of the time-dependent properties within a polymicrobial community at various stages of biofilm development. This work demonstrates the importance of growth kinetics in the bacteria competition for the interface in a model dual-species biofilm.

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Posted in Bacillus, Bacillus licheniformis, Biofilm, Food Micro Blog, Food Microbiology Blog, microbial contamination, Microbiology, Pseudomonas, Pseudomonas fluorescens