Category Archives: Research

Research – Impact of Quercetin against Salmonella Typhimurium Biofilm Formation on Food–Contact Surfaces and Molecular Mechanism Pattern

Posted on April 7, 2022 by | Leave a comment

MDPI

Quercetin is an active nutraceutical element that is found in a variety of foods, vegetables, fruits, and other products. Due to its antioxidant properties, quercetin is a flexible functional food that has broad protective effects against a wide range of infectious and degenerative disorders. As a result, research is required on food-contact surfaces (rubber (R) and hand gloves (HG)) that can lead to cross-contamination. In this investigation, the inhibitory effects of quercetin, an antioxidant and antibacterial molecule, were investigated at sub-MIC (125; 1/2, 62.5; 1/4, and 31.25; 1/8 MIC, μg/mL) against Salmonella Typhimurium on surfaces. When quercetin (0–125 μg/mL) was observed on R and HG surfaces, the inhibitory effects were 0.09–2.49 and 0.20–2.43 log CFU/cm2, respectively (p < 0.05). The results were confirmed by field emission scanning electron microscopy (FE-SEM), because quercetin inhibited the biofilms by disturbing cell-to-cell connections and inducing cell lysis, resulting in the loss of normal cell morphology, and the motility (swimming and swarming) was significantly different at 1/4 and 1/2 MIC compared to the control. Quercetin significantly (p < 0.05) suppressed the expression levels of virulence and stress response (rpoS, avrA, and hilA) and quorum-sensing (luxS) genes. Our findings imply that plant-derived quercetin could be used as an antibiofilm agent in the food industry to prevent S. Typhimurium biofilm formation. View Full-Text

Leave a comment

Posted in Biofilm, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Salmonella

Research – Levels and genotypes of Salmonella and levels of Escherichia coli in frozen ready-to-cook chicken and turkey products in England tested in 2020 in relation to an outbreak of S. Enteritidis

Posted on April 7, 2022 by | Leave a comment

PubMed

Frozen reformulated (FR) breaded chicken products have previously been implicated in causing human salmonellosis. A multi-country Salmonella enterica serovar Enteritidis outbreak involving several strains with >400 reported human cases in the UK occurred in 2020. Initially S. Infantis was detected in one sample from a case home but S. Enteritidis was then also isolated using a S. Enteritidis specific PCR in combination with isolation via a Craigie-tube. This prompted a survey to examine the presence and levels of Salmonella and E. coli in ready-to-cook FR poultry products in England in 2020. From a total of 483 samples, including two from cases’ homes, Salmonella was detected in 42 chicken samples, these originated from six out of 53 production plants recorded. Salmonella detection was associated with elevated levels of generic E. coli (OR = 6.63). S. Enteritidis was detected in 17 samples, S. Infantis in 25, S. Newport in four and S. Java, S. Livingstone and S. Senftenberg in one each. The highest levels of Salmonella were 54 MPN/g for S. Infantis and 28 MPN/g for S. Enteritidis; 60% of the Salmonella-positive samples had <1.0 MPN/g. S. Enteritidis was detected together with S. Infantis in five samples and with S. Livingstone in one. Where S. Enteritidis was detected with other Salmonella, the former was present at between 2 and 100-fold lower concentrations. The Salmonella contamination was homogeneously distributed amongst chicken pieces from a single pack and present in both the outer coating and inner content. The S. Enteritidis were all outbreak strains and detected in six products that were linked to four production plants which implicated a Polish origin of contamination. Despite S. Infantis being most prevalent in these products, S. Infantis from only two contemporaneous human cases in the UK fell into the same cluster as isolates detected in one product. Except for one human case falling into the same cluster as one of the S. Newport strains from the chicken, no further isolates from human cases fell into clusters with any of the other serovars detected in the chicken samples. This study found that higher E. coli levels indicated a higher probability of Salmonella contamination in FR chicken products. The results also highlight the importance of recognising co-contamination of foods with multiple Salmonella types and has provided essential information for detecting and understanding outbreaks where multiple strains are involved.

Leave a comment

Posted in Decontamination Microbial, food bourne outbreak, Food Illness, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Foodborne Illness, foodborne outbreak, foodbourne outbreak, Illness, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, outbreak, Polish Chicken Salmonella, Research, Salmonella, Salmonella in Chicken, Salmonella Poland, salmonellosis

Research – Vital Surveillances: Phylogenetic Analysis of Serogroup O5 Vibrio cholerae that Caused Successive Cholera Outbreaks — Guangdong Province, China, 2020–2021

Posted on April 6, 2022 by | Leave a comment

China CDC

Food Illness

  • Abstract

    IntroductionGastroenteritis caused by non-O1/non-O139 Vibrio cholerae exhibited an increasing trend in recent years in China. Whole genome sequence (WGS) data could play an important role both in the identification of the outbreaks and in the determination of the serogroup. Here, we present the employment of WGS data in the investigation of two outbreaks caused by non-O1/non-O139 V. cholerae in Guangdong, China, 2020–2021.

    MethodsWe obtained the whole genome sequence of 66 V. cholerae strains isolated in two outbreaks with next generation sequencing technology. We retrieved the publicly available WGS data of non-O1/non-O139 V. cholerae from public database. We used a pipeline integrated in China Pathogen Identification Net (PIN) to complete the phylogenetic analysis.

    ResultsTwo outbreaks caused by non-O1/non-O139 V. cholerae were identified using WGS data. These V. cholerae strains were determined as serogroup O5. Type 3 and 6 secretion systems were detected in these serogroup O5 strains. These serogroup O5 strains belonged to sequence type (ST) 88.

    ConclusionsOur analysis indicated the risk of non-O1/non-O139 V. cholerae of leading to outbreaks of diarrheal diseases. The application of genomic data played important role in the identification of the serogroup of non-O1/non-O139 V. cholerae in the lack of antiserum, which gave an example of the application of genome data in disease surveillance and public health emergency response.

  • Vibrio cholerae consists of more than 200 serogroups. The classification of serogroups is based on the O antigen of the lipopolysaccharide (LPS) (1). The classical method of serogroup determination is based on the immune agglutination reaction between the O antigen and the corresponding specific antiserum. The molecular mechanisms of different serogroups are based on the variation in structure of O-antigen polysaccharide (O-PS) coding sequence (2). Therefore, the phenotype of O-antigen is correlated with the molecular type of O-PS coding sequence. Till now, only serogroup O1 and O139 V. cholerae caused cholera epidemics and pandemics (3). V. cholerae does not belong to serogroup O1 and O139 and are designated as “non-O1/non-O139” V. cholerae. Usually, these non-O1/non-O139 V. cholerae only cause sporadic infections and seldomly cause outbreaks (4). Several kinds of toxins, such as a heat-stable toxin, cholera toxin, and other enterotoxins, have been detected in the non-O1/non-O139 V. cholerae that caused an outbreak. Except for the toxins, secretion systems, for example type 3 secretion system (T3SS) and type 6 secretion system, have been detected in some V. cholerae strains that caused cholera outbreaks (5).

    In China, toxigenic serogroup O1 and O139 V. cholerae strains were rarely isolated after 2010 (6). In contrast, sporadic cholera cases even small scale of outbreaks caused by non-O1/non-O139 V. cholerae were reported from time to time (4). Here we report successive cholera outbreaks caused by non-toxin-producing serogroup O5 V. cholerae in 2020 and 2021 in Guangdong Province, China.

Leave a comment

Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Vibrio, Vibrio cholera, vibrio cholerae

Research – ‘Tainted’ audiobook now available

Posted on April 6, 2022 by | Leave a comment

Food Safety News

Tainted by Phyllis Entis

Phyllis Entis’s new book “Tainted” is now available as an audiobook. The book is narrated by Entis herself.

The book is particularly topical as the first chapter talks about Cronobacter sakazakii, a dangerous bacterium that has caused an ongoing outbreak. The cronobacter outbreak has sickened at least five infants, killing two, and has been linked to Similac, Alimentum, and EleCare infant formulas recalled Abbott Nutrition.

“Tainted” tells readers that when it comes to food safety, conventional wisdom isn’t always enough. As Entis puts it, “the food preparation skills we learned from our parents and grandparents are no longer good enough to keep us safe.”

Phyllis Entis

The audiobook can be found here.

Leave a comment

Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research

Research – Campylobacter in Southeast Asia infects about 7.8% according to new study

Posted on April 5, 2022 by | Leave a comment

Food Poisoning News

Infections from the bacterium Campylobacter are among the most common causes of food poisoning, and a new study has found that these infections are also common in Southeast Asia.

The study published in the International Journal of Infectious Diseases, which was a meta-analysis and systematic review of data from 51 studies, found that the overall prevalence of Campylobacter infections in Southeast Asia is 7.8%. This means that for every 1,000 people in Southeast Asia, about 78 will have an infection from this bacterium at some point. The study also found that there is a lot of variation in the prevalence of these infections between different countries in Southeast Asia. For example, the prevalence in Thailand is 13.3%.

There are many different ways that people can get infected with Campylobacter, but the most common is through eating contaminated food. The bacteria can also be spread through contact with animals, particularly poultry. Symptoms of a Campylobacter infection include diarrhea, cramping, and fever. Most people will recover from the infection without any treatment, but in some cases it can lead to more serious problems like pneumonia or meningitis.

Leave a comment

Posted in campylobacter coli, Campylobacter jejuni, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research

Research – Salmonella spp. Response to Lytic Bacteriophage and Lactic Acid on Marinated and Tenderized Raw Pork Loins

Posted on April 5, 2022 by | Leave a comment

MDPI

Bacterial food poisoning cases due to Salmonella have been linked with a variety of pork products. This study evaluated the effects of a Salmonella-specific lytic bacteriophage and lactic acid (LA) on Salmonella Enteritidis, Salmonella Montevideo, and Salmonella Heidelberg growth on raw pork loins. Pork loins were cut into approximately 4 cm thick slices. Pork slices were randomly assigned to five treatment groups (control, DI water, LA 2.5%, phage 5%, and LA 2.5% + phage 5%) with six slices per group per replication. Pork loins were inoculated with 106 CFU/mL of Salmonella spp. and stored at 4 °C for 30 min. After 1 h of treatment application and marination, phage 5% significantly (p < 0.05) reduced the surface bacterial population by 2.30 logs when compared with the control group. Moreover, the combined treatment of LA 2.5% + phage 5% significantly (p < 0.05) reduced the surface bacterial population by more than 2.36 logs after 1 h of marination. In the post-tenderization surface samples, the combination of both phage and LA showed a significant reduction (p < 0.05) when compared with the control group. However, the treatments had no effect (p > 0.05) when analyzing the translocation of pathogens on pork loins. View Full-Text

Leave a comment

Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Salmonella

Research – Water application method influences survival or growth of Escherichia coli on bulb onions during field curing

Posted on April 4, 2022 by | Leave a comment

FDA

The impact of water application method on bacterial survival at or after the final irrigation was evaluated in bulb onions during commercially relevant field-drying (curing). A three-strain rifampin-resistant cocktail of Escherichia coli was introduced to onions via a single overhead spray application in two separate trials (5.22 [trial 1] or 2.40 [trial 2] log CFU per onion) 2 to 3 days after the final irrigation. Onions were lifted from the soil 8 days after spray inoculation and, in some cases, foliage was removed (topping); onions remained in the field for an additional ca. 2 weeks (total ca. 3 weeks of curing). E. coli populations declined on the onions in the first 4 h after spray inoculation. E. coli was recovered from 48% (38 of 80) or 35% (28 of 80) of whole-onion enrichments at the end of curing in trials 1 or 2, respectively. Topping did not significantly impact the percentage of E. coli–positive onions detected at the end of curing. From 8 h to 21 days, E. coli populations on positive onions ranged from 1 CFU per onion to 7 log CFU per onion in both trials, representing a potential risk of E. coli growth with overhead application of contaminated water at the end of onion production. In trial 2, additional rows of onions were inoculated via a 22-cm subsurface or surface drip irrigation line (1.94 log CFU/mL for 2.5 h). E. coli was detected in 0 of 50 (subsurface) or 4 of 50 (surface) whole-onion enrichments 3 h after the initiation of drip irrigation. Positive onions were detected at days 1 (4 of 50) and 7 (1 of 50) with subsurface drip inoculation, and at days 1 (7 of 50), 7 (2 of 50), or 14 (2 of 50) with surface drip inoculation. E. coli was not detected in whole-onion enrichments at the end of curing when inoculated by subsurface (0 of 50) or surface (0 of 50) drip irrigation. Application of contaminated water through drip irrigation, when coupled with field curing, results in low rates of contamination of bulb onions at the time of harvest.

Leave a comment

Posted in Decontamination Microbial, E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research

Research – Evaluation of the Persistence and Characterization of Listeria monocytogenes in Foodservice Operations

Posted on April 4, 2022 by | Leave a comment

MDPI

Listeria monocytogenes is a major foodborne pathogen that can contaminate food products and colonize food-producing facilities. Foodservice operations (FSOp) are frequently responsible for foodborne outbreaks due to food safety practices failures. We investigated the presence of and characterized L. monocytogenes from two FSOp (cafeterias) distributing ready-to-eat meals and verified FSOp’s compliance with good manufacturing practices (GMP). Two facilities (FSOp-A and FSOp-B) were visited three times each over 5 months. We sampled foods, ingredients, and surfaces for microbiological analysis, and L. monocytogenes isolates were characterized by phylogenetic analyses and phenotypic characteristics. GMP audits were performed in the first and third visits. A ready-to-eat salad (FSOp-A) and a frozen ingredient (FSOp-B) were contaminated with L. monocytogenes, which was also detected on Zone 3 surfaces (floor, drains, and a boot cover). The phylogenetic analysis demonstrated that FSOp-B had persistent L. monocytogenes strains, but environmental isolates were not closely related to food or ingredient isolates. GMP audits showed that both operations worked under “fair” conditions, and “facilities and equipment” was the section with the least compliances. The presence of L. monocytogenes in the environment and GMP failures could promote food contamination with this pathogen, presenting a risk to consumers. View Full-Text

Leave a comment

Posted in Decontamination Microbial, food bourne outbreak, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, foodborne outbreak, foodbourne outbreak, Listeria, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, outbreak, Research

Research – Surveillance of Antimicrobial Resistance (AMR) in E. coli and Campylobacter from retail turkey meat and E. coli from retail lamb in 2020/21-FS102109

Posted on April 2, 2022 by | Leave a comment

APHA

ecoli

This report presents results of the surveillance of antimicrobial resistance (AMR) in specific bacteria, i.e., Campylobacter and Escherichia coli (E.coli)from lamb and turkey meats on retail sale in the UK between October 2020 and February 2021.
The aim was to test by culture approximately 200 samples each of lamb and turkey meat for E.coli, and also to test the turkey samples for Campylobacter. The FSA requested testing of lamb and turkey meat as the majority of AMR surveys on UK retail meats have focused on beef, chicken and pork.
As such there is an evidence gap for AMR in lamb and turkey meat. E. coli is a normal inhabitant of the mammalian and avian gut and most isolates do not cause observable clinical disease in healthy animals and humans. Therefore, E.coli isolates can be useful “indicators” of AMR in gut bacteria. Campylobacter is frequently present in the gut of healthy poultry, and thermophilic species (Campylobacter jejuni and Campylobacter coli) typically cause food poisoning in humans.
The monitoring of lamb and turkey meat for AMR is not mandatory as part of the European Directive 2003/99/EC, but the methodology used in this survey was broadly based on the current EU methodologies for the testing of retail beef, chicken and pork. These methodologies involve culture of E. coli on selective agar media containing the antimicrobial drug cefotaxime. Growth of E. coli on such plates indicate resistance to third generation cephalosporin antimicrobial drugs, including extended-spectrum beta lactamase (ESBL) and Amp C type resistance. Such isolates should be further tested for susceptibility to a panel of antimicrobials by determining minimum inhibitory concentration (MIC) values using a broth dilution method based on EN ISO 20776-1:2006.As recommended by the EU, additional selective cultures were performed on samples to isolate any E.coli resistant to carbapenem antimicrobials. Carbapenems are termed ‘last resort’ drugs, used to treat severe infections when other treatment options are ineffective because of multiple resistances in the target Gram negative bacteria.

6At the request of the FSA (non-harmonised testing outside the remit of Decision 2013/652/EU) further screening was performed for E.coli strains resistant to colistin (another ‘last resort’ human antimicrobial drug) and those specifically producing ESBL resistance enzymes. Colistin-resistant strains may harbour mcr resistance genes, which are located on plasmids that can transfer between bacteria.

Leave a comment

Posted in Antibacterial, antimicrobial resistance, Antimicrobials, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research

Research – Evaluation of Hygiene Indicators and Sampling Plan for Detecting Microbial Contamination in Health Functional Foods

Posted on April 2, 2022 by | Leave a comment

Journal of Food Protection

This study aimed to monitor microbial contamination level in a variety of health functional foods and to establish new microbial criteria. Indicator organisms (i.e., aerobic bacteria, coliform bacteria, and Escherichia coli ) were monitored in 10 health functional food categories (743 items, 3,715 samples). The mean total aerobic counts of ginseng and Korean red ginseng were -0.35 and -0.74 log10 CFU/g; and their mean total coliform counts were -1.4 and -1.39 log10 CFU/g, respectively. In addition, the mean total coliform counts of fiber and protein products were -1.34 and -1.22 log10 CFU/g, respectively. However, no aerobic or coliform cells were detected in any other health functional food products (vitamins, minerals, probiotics, milk thistle extract, propolis, eicosapentaenoic acid, docosahexaenoic acid, or lutein products), and no E. coli was detected in any of the categories. These results can potentially be used to update the microbial criteria of the Health Functional Food Code.

Leave a comment

Posted in Coliforms, E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Technology