Category Archives: Food Microbiology

USA -Dozens of norovirus-like cases linked to Brave Horse Tavern

Outbreak News Today

Food Borne Illness - Norovirus -CDC Photo

Image CDC

Public Health — Seattle & King County is reporting some 43 cases of a norovirus-like illness linked to a Seattle restaurant.

Officials say the outbreak is associated with Brave Horse Tavern on 310 Terry Ave N, in  Seattle. The patients experienced symptoms of vomiting, diarrhea, body aches, chills, and fever.

Health officials report:

Since November 27, 2019, 30 people from 5 meal parties reported becoming ill after consuming food and drinks from Brave Horse Tavern on November 23 and 24, 2019.

We identified at least 11 employees who experienced symptoms consistent with norovirus dating back to November 24, 2019. At least 2 employees had 2 total household members with symptoms dating back to November 20, 2019.

Research – Inactivation kinetics of inoculated Escherichia coli and Listeria innocua in fresh‐cut Chinese cabbage using sweeping frequency ultrasound

Wiley Online

Abstract

Sweeping frequency ultrasound washing is a recent technology of applying varying ultrasound frequencies in the decontamination of fresh produce. Ultrasound inactivation of Escherichia coli and Listeria innocua inoculated on fresh‐cut Chinese cabbage was investigated at sweeping frequencies of 28 ± 2 to 68 ± 2 kHz for washing time of 5–40 min. The survival ratio of Ecoli and Linnocua decreased with the time of exposure to ultrasound washing and varying frequencies. Ecoli were more sensitive to ultrasound washing than Linnocua, achieving >3.0 log reductions after 10 min of washing with 40 ± 2 kHz. A nonlinear Weibull model was used to describe the experimental data, and the fitness of the model was evaluated by the coefficient of determination (R2) and the root mean square error (RMSE). The model used provided a good fit with R2 ≥ .98 for both bacteria and RMSE values in the range of 0.03–0.21 and 0.02–0.32 for E. coli and L. innocua, respectively.

Practical Application

Ultrasound decontamination is an alternative nonthermal technology that has been applied in recent years to improve the microbial safety of fresh produce. The bacterial inactivation is predominantly attributed to cavitation, an occurrence that interrupts cellular arrangement and function. With the known significance of sanitization in the processing of vegetables, it is imperative to develop and appraise novel approaches that contribute to the microbial safety of these fresh produce. Largely, the results of our study could guide the design of new ultrasonic fresh produce wash systems in addition to current industrial practice related to frequency selection and use of ultrasound during fresh produce sanitation.

Research – Interaction and inactivation of Listeria and Lactobacillus cells in single and mixed species biofilms exposed to different disinfectants

Wiley Online

Abstract

Listeria spp. are ubiquitously found in both the natural and the food processing environment, of which Listeria monocytogenes is of an important health risk. Here, we report on the formation of single and mixed species biofilms of L. monocytogenes/Listeria innocua and Lactobacillus plantarum strains in 24‐well polystyrene microtiter plates and on the inactivation of 24‐hr and 72‐hr biofilms using quaternary ammonium compound‐, tertiary alkyl amine‐, and chlorine‐based disinfectants. Fluorescent in situ hybridization (FISH) and LIVE/DEAD BacLight staining were applied for 72‐hr L. innocuaL. plantarum mixed biofilms in the LabTek system for the species identification and the reaction of biofilm cells to disinfectants, respectively. L. monocytogenes/L. innocua were more resistant to disinfectants in 72‐hr than in 24‐hr biofilms, whereas L. plantarum strains did not show any significant differences between 72‐hr and 24‐hr biofilms. Furthermore, L. innocua when grown with L. plantarum was more resistant to all disinfection treatments, indicating a protective effect from lactobacilli in the mixed species biofilm. The biofilm formation and reaction to disinfectants, microscopically verified using fluorescence in situ hybridization and LIVE/DEAD staining, showed that L. innocua and L. plantarum form a dense mixed biofilm and also suggested the shielding effect of L. plantarum on L. innocua in the mixed species biofilm.

Research – Identification and genotyping of Listeria monocytogenes in the chicken shredding line

Wiley Online

Abstract

The present research was carried out to determine the presence of Listeria monocytogenes in the equipment, staff, and products in the chicken shredding facilities operating in Samsun, and to serotype and genotype the isolates by PCR and PFGE analysis, respectively. Of the total of 192 samples tested, 25 were found to be L. monocytogenes positive from which 51 isolates were acquired. In serotyping of the 51 isolates; 47 (92.2%) and four isolates (7.8%) were identified as 1/2a (3a) and 1/2c (3c), respectively. Twenty‐six of the 51 isolates (51%) were resistant to at least one antibiotic, and 13 (25.5%) were resistant to more than one antibiotic. In the PFGE evaluation, at least 80% similarity was taken as a basis, and in the dendrogram, it was determined as a result of restricting with the Apal enzyme that the isolates were distributed to 25 different clusters and 45 subsets, and as a result of restricting with the AscI enzyme, they were distributed to 29 different clusters and 36 subsets.

Practical Application

Listeria monocytogenes constitutes a major problem for the food industry due to its widespread availability in nature and its role as an environmental contaminant in food processing plants.

Research – Listeria monocytogenes in dairy plants in Southern Brazil: Occurrence, virulence potential, and genetic diversity

Wiley Online

Abstract

Listeria monocytogenes is a foodborne pathogen widely distributed in nature. The aims of this study were to evaluate the occurrence of Listeria spp. in three dairy plants located in Southern Brazil, and to characterize the Lmonocytogenes isolates according to serotypes, virulence genes, and PFGE. A total of 212 samples were collected, and 15 were positive for Listeria spp., of which seven were LmonocytogenesLmonocytogenes isolates harbored all the 11 virulence genes evaluated and belonged to the main virulent serotypes, indicating potential risks of listeriosis for consumers. The PFGE analysis indicated low genetic diversity among the isolates, and the same pulsotypes were detected in a 2‐month period, indicating persistence of Lmonocytogenes.

Practical applications

The study evaluated the occurrence of Listeria spp. in three dairy plants located in Southern Brazil, as well as characterized the L. monocytogenes isolates according to serotypes, virulence genes and PFGE. The presence of Listeria species indicated postprocessing contamination in the dairy plants and threat to public health. Furthermore, the isolates showed a low genetic diversity, since only two pulsotypes were identified, highlighting the strain’s persistence in the processing environment and/or the presence of clones in this region.

Canada – Food Recall Warning – Amsellem brand Solo Chorizo – Dried Beef Sausage recalled due to Salmonella

CFIA

Recall details

Ottawa, December 4, 2019 – Usine Amsellem Inc. is recalling Amsellem brand Solo Chorizo – Dried Beef Sausage from the marketplace due to possible Salmonella contamination. Consumers should not consume the recalled product described below.

Recalled product

Brand Product Size UPC Codes
Amsellem Solo Chorizo – Dried Beef Sausage 28 g 6 28055 38930 9 91002DC-707
BB 2020 AVR 08

Illnesses

There have been no reported illnesses associated with the consumption of this product.

Product photos

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  • Amsellem - Solo Chorizo – Dried Beef Sausage

Research – Massachusetts General Hospital publishes new Shigella research

Outbreak News Today

The bacterial pathogen Shigella, often spread through contaminated food or water, is a leading cause of mortality in both children and older adults in the developing world. Although scientists have been studying Shigella for decades, no effective vaccine has been developed, and the pathogen has acquired resistance to many antibiotics. The recent discovery of an early adherence step in the infection cycle by researchers at Massachusetts General Hospital (MGH) could provide a new therapeutic target or even a new method for vaccine development.

As it moves through the digestive system, Shigella traverses the small intestine and subsequently infects the large intestine, causing cramping, diarrhea and dehydration in the disease called shigellosis. “We wanted to determine how Shigella makes its first contact with epithelial cells in the early stages of disease development,” says Dr. Christina Faherty, senior author on the study published in mSphere. “Because of certain gene sequence annotations, and the way that Shigella appeared following growth in standard laboratory media, it was believed that Shigella strains do not produce fimbriae or other adherence factors.” Fimbriae are short hair-like fibers that bacterial cells use to adhere to individual epithelial cells to instigate infection.