Category Archives: Microbiological Risk Assessment

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

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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 – Viability of Shiga Toxin-Producing Escherichia coli, Salmonella spp., and Listeria monocytogenes During Preparation and Storage of Fuet, a Traditional Dry-Cured Spanish Pork Sausage

Posted on April 3, 2022 by | Leave a comment

Journal of Food Protection

We monitored viability of Shiga toxin-producing Escherichia coli (STEC), Salmonella spp., and Listeria monocytogenes during preparation and storage of fuet. Coarse ground pork (ca. 35% fat) was mixed with salt (2.5%), dextrose (0.3%), starter culture (ca. 7.0 log CFU/g), celery powder (0.5%), and ground black pepper (0.3%), and then separately inoculated with a multi-strain cocktail (ca. 7.0 log CFU/g) of each pathogen. The batter was stuffed into a ca. 42-mm natural swine casing and fermented at 23°C and ca. 95% relative humidity (RH) to ≤pH 5.3 (≤ 48 h). Sausage were then dried at 12°C and ca. 80% RH to a w 0.89 (within 33 days) or a w  0.86 (within 60 days). A portion of each batch of fuet was subjected to high pressure processing (HPP; 600 MPa/3 min) before chubs were vacuum-packaged and stored for 30 days at 20°C. After fermentation, pathogen numbers remained relatively unchanged (≤0.35 log CFU/g reduction), whereas reductions of ca. 0.8 to 3.2 log CFU/g were achieved after drying fuet to a w 0.89 or 0.86. Regardless if fuet was or was not pressure treated, additional reductions of ca. 2.2 to ≥5.3 log CFU/g after drying were achieved following 30 days of storage at 20°C. For non-HPP treated fuet dried to a w 0.89 and stored for 30 days at 20°C, total reductions of ≥5.3 log CFU/g in levels of STEC or Salmonella spp. were achieved, whereas levels of L. monocytogenes were reduced by ca. 3.6 log CFU/g. Total reductions of ≥5.3 log CFU/g in levels of all three pathogens were achieved after drying non-HPP treated fuet to a w 0.86. For fuet dried to a w 0.89 or   0.86, pressure treated, and then stored for 30 days at 20°C, total reductions of >6.2 log CFU/g in levels of all three pathogens were achieved. The processing parameters tested herein, with or without application of HPP, validated reductions of ≥2.0- or ≥5.0-log CFU/g in levels of STEC, Salmonella spp., and L. monocytogenes were achieved during preparation and storage of fuet.

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

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.

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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.

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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

Research – Quantitative Microbial Risk Assessment of Listeria monocytogenes and Enterohemorrhagic Escherichia coli in Yogurt

Posted on April 1, 2022 by | Leave a comment

MDPI

Listeria monocytogenes can survive in yogurt stored at a refrigeration temperature. Enterohemorrhagic Escherichia coli (EHEC) has a strong acid resistance that can survive in the yogurt with a low pH. We estimated the risk of L. monocytogenes and EHEC due to yogurt consumption with @Risk. Predictive survival models for L. monocytogenes and EHEC in drinking and regular yogurt were developed at 4, 10, 17, 25, and 36 °C, and the survival of both pathogens in yogurt was predicted during distribution and storage at home. The average initial contamination level in drinking and regular yogurt was calculated to be −3.941 log CFU/g and −3.608 log CFU/g, respectively, and the contamination level of both LM and EHEC decreased in yogurt from the market to home. Mean values of the possibility of illness caused by EHEC were higher (drinking: 1.44 × 10−8; regular: 5.09 × 10−9) than L. monocytogenes (drinking: 1.91 × 10−15; regular: 2.87 × 10−16) in the susceptible population. Both pathogens had a positive correlation with the initial contamination level and consumption. These results show that the foodborne illness risk from L. monocytogenes and EHEC due to yogurt consumption is very low. However, controlling the initial contamination level of EHEC during yogurt manufacture should be emphasized.

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Posted in Decontamination Microbial, EHEC, escherichia coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Listeria, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research

Research – Plant Extract and Essential Oil Application against Food-Borne Pathogens in Raw Pork Meat

Posted on April 1, 2022 by | Leave a comment

MDPI

Herbal and plant extracts are being applied for a wide range of foods against different types of food-borne pathogens. In the present study, ethanolic and aqueous extracts (2% w/v) from cranberry (Vaccinium macrocarpon) and pomegranate (Punica granatum L.) plants were applied alone or in combination with two essential oils (thyme and oregano in a concentration of 0.150 μg/g) in pork meatballs and their antimicrobial activity was estimated. The extracts exhibited promising results (aqueous and ethanolic extracts of pomegranate and cranberry in a food-compatible concentration of 2% w/v) were applied to raw pork meatball production and their antimicrobial activity was recorded versus Enterobacteriaceae, total mesophilic bacteria, yeasts/molds, Staphylococcus spp., Pseudomonas spp. and lactic acid bacteria (LAB). The outcome demonstrated that meatballs containing aqueous extracts of pomegranate were more resistant to spoilage compared to all the other samples since they were preserved for more days. The chemical profiles of plant extracts were determined through LC-QTOF/MS and the chemical composition of the essential oils applied was determined with the use of GC/MS in order to identify the substances involved in the observed antimicrobial activity. Phenolic acids (quinic acid, chlorogenic acid), monoterpenes (p-cymene, carvacrol, thymol, limonene), organic acids (citric acid) and phenols were the main constituents found in the plant extracts and essential oils applied. These extracts of plant origin could be used as natural preservatives in meat products, even in low concentrations. View Full-Text

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Posted in Decontamination Microbial, Enterobacteriaceae, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, lactic acid bacteria, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Pseudomonas, Research, Staphylococcus aureus

Food poisoning or hangover? Here’s how you can tell the difference

Posted on April 1, 2022 by | Leave a comment

Food Poisoning News

When you drink too much alcohol at night, you may wake up feeling sick the next day. The majority of people assume it’s another awful hangover, but there’s a chance that food poisoning or even alcohol poisoning could be to blame. Because both food poisoning and a hangover might induce nausea, vomiting, and headaches, determining whether you’re experiencing one of them can be tough.

A few key characteristics can help you figure out if it’s food poisoning or a hangover. If you have a fever, chills, and body aches, it’s more likely to be food poisoning. If you have a throbbing headache and feel very thirsty with a dry mouth, it’s more likely to be a hangover. Other symptoms like diarrhea are common to both conditions.

Let’s look into both hangovers and food poisoning in further detail at the link above.

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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 – Vehicle Windshield Wiper Fluid as Potential Source of Sporadic Legionnaires’ Disease in Commercial Truck Drivers

Posted on March 31, 2022 by | Leave a comment

CDC

Abstract

Sporadic Legionnaires’ disease is frequently detected in commercial truck drivers. We report 2 sporadic cases of this disease in Barcelona, Spain, that occurred during December 2019 and September 2020. Laboratory findings were consistent with windshield wiper fluid without added screen wash as a possible source of infection for both cases.

Legionnaires’ disease is a severe form of acute pneumonia caused by inhalation of aerosols containing Legionella bacteria. Most Legionella infections are related to contaminated artificial water systems. Systems with warm water (35°C), stagnation, and lack of disinfection and maintenance can lead to proliferation of Legionella spp. . Cooling towers, warm water systems, and whirlpool spas are well-established sources of infection . However, in most sporadic cases, the source of infection remains unknown.

Commercial truck drivers are at increased risk for Legionnaires’ disease. Exposures related to the vehicle are usually considered secondary to outside sources in industrial areas, such as cooling towers, and are seldomley investigated, despite some studies suggesting them as potential sources. Using windshield wiper fluid without added screen wash has been identified as a risk factor for Legionnaires’ disease in commercial drivers in a previous case‒control study. In addition, Legionella spp. can grow in windshield wiper fluid that does not contain screen wash. However, no studies have epidemiologically confirmed the fluid as the source of infection. We report 2 cases of Legionnaires’ disease cases diagnosed by urine antigen testing (UAT) linked to detection of the bacteria in the windshield wiper fluid.

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Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Legionella, Legionnaires’ disease, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research

Research – Inhibition of Listeria monocytogenes by Phage Lytic Enzymes Displayed on Tailored Bionanoparticles

Posted on March 31, 2022 by | Leave a comment

MDPI

The high mortality rate associated with Listeria monocytogenes and its ability to adapt to the harsh conditions employed in food processing has ensured that this pathogen remains a serious problem in the ready-to-eat food sector. Bacteriophage-derived enzymes can be applied as biocontrol agents to target specific foodborne pathogens. We investigated the ability of a listeriophage endolysin and derivatives thereof, fused to polyhydroxyalkanoate bionanoparticles (PHA_BNPs), to lyse and inhibit the growth of L. monocytogenes. Turbidity reduction assays confirmed the lysis of L. monocytogenes cells at 37 °C upon addition of the tailored BNPs. The application of BNPs also resulted in the growth inhibition of L. monocytogenes. BNPs displaying only the amidase domain of the phage endolysin were more effective at inhibiting growth under laboratory conditions (37 °C, 3 × 107 CFU/mL) than BNPs displaying the full-length endolysin (89% vs. 83% inhibition). Under conditions that better represent those found in food processing environments (22 °C, 1 × 103 CFU/mL), BNPs displaying the full-length endolysin demonstrated a greater inhibitory effect compared to BNPs displaying only the amidase domain (61% vs. 54% inhibition). Our results demonstrate proof-of-concept that tailored BNPs displaying recombinant listeriophage enzymes are active inhibitors of L. monocytogenes. View Full-Text

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Posted in Bacteriophage, Decontamination Microbial, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, Listeria, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Technology

Research – Enhanced antimicrobial effectiveness of synergistic mixtures of rambutan peel extract and cinnamon essential oil on food spoilage bacteria and bio-based food packaging

Posted on March 31, 2022 by | Leave a comment

Wiley Online

Staph

This research aims to enhance antimicrobial activity of rambutan peel extract (RPE), by mixing with cinnamon essential oil (CEO). The mixture of RPE and CEO with different weight ratios (10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9, and 0:10) had been prepared and the antimicrobial efficacy was tested. Nine strains of bacteria: Gram-positive bacteria (Bacillus sp., Enterococcus faecalis, Leuconostoc sp., Micrococcus luteus, Staphylococcus aureus, and Streptococcus sp.) and Gram-negative bacteria (Escherichia coli, Pseudomonas fluorescens, and Salmonella typhimurium) were selected as the representative of pathogenic and food spoilage bacteria. Mixing RPE with CEO in a ratio of 5:5 showed the best synergistic effect against those bacteria. Addition of RPE/CEO in a weight ratio of 5:5 improved the antimicrobial activity of whey protein isolated (WPI) films, and enhanced strength, stiffness, and water resistance of the film.

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Posted in Bacillus, Decontamination Microbial, E.coli, Faecal Streptpcocci, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Pseudomonas fluorescens, Research, Salmonella, Staphylococcus aureus, Technology