Category Archives: Research

Research -Persistent contamination of Salmonella, Campylobacter, Escherichia coli, and Staphylococcus aureus at a broiler farm in New Zealand

Posted on February 18, 2020 by | Leave a comment

Canadian Journal of Microbiology

Intensive poultry production due to public demand raises the risk of contamination, creating potential foodborne hazards to consumers. The prevalence and microbial load of the pathogens Campylobacter, Salmonella, Staphylococcus aureus, and Escherichia coli was determined by standard methods at the farm level. After disinfection, swab samples collected from wall crevices, drinkers, and vents were heavily contaminated, as accumulated organic matter and dust likely protected the pathogens from the disinfectants used. The annex floor also showed high microbial concentrations, suggesting the introduction of pathogens from external environments, highlighting the importance of erecting hygiene barriers at the entrance of the main shed. Therefore, pathogen control measures and proper application of disinfectants are recommended as intervention strategies. Additionally, quantitative polymerase chain reaction (qPCR) was evaluated as a quantification tool. qPCR showed limitations with samples containing low microbial counts because of the low detection limit of the method. Thus, bacterial pre-enrichment of test samples may be necessary to improve the detection of pathogens by qPCR.

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Posted in Campylobacter, E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiology, Research, Salmonella, Staphylococcus aureus, Uncategorized

Research – Effects of coating pistachio kernels with mixtures of whey protein and selected herbal plant extracts on growth inhibition of Aspergillus flavus and prevention of aflatoxin during storage

Posted on February 17, 2020 by | Leave a comment

Wiley Online

Whey protein concentrate (WPC) mixed with various concentrations of Shirazi thyme (ST), sage, and cumin seed (CS) extracts separately. Then pistachio kernels (PK) contaminated with Aspergillus flavus (Af) were coated with each extract and the Af mycelium and generated aflatoxins measured after 3, 5, and 7‐days at 20°C. The ST, sage, and CS had two major antioxidants of thymol (~27%) and carvacrol (~41%), α‐thujone (~28%) and camphor (~14%), and cumin‐aldehyde (~21%) and safranal (~20%), respectively. While the Af mycelium diameter on PK without extract became >90 mm within 3 days, it was shrunk after 7 days when the WPC‐coated PK had 4,000 ppm ST extract. When ST concentrations increased in WPC‐coated PK linearly, the Af growth and aflatoxins production decreased logarithmically. No aflatoxins (B1, B2, G1, and G2) detected in PK after 9 days when the extract concentrations of ST, sage, and CS in WPC reached, respectively to 5,000, 4,500, and 6,500 ppm. Sage extract had significantly (p < .01) the highest TPC (lowest IC50) and preventing power for aflatoxin generation in comparison with ST and CS extracts. The PK will be safe and healthy if the extract concentration of sage, ST, and CS exceed 950, 1,400, and 1,700 mg/kg, respectively.

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Posted in Aflatoxin, Aspergillus, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, Food Toxin, microbial contamination, Microbiology, Mould Toxin, Mycotoxin, Research, Uncategorized

Research – How Temperature Influences Legionella Growth

Posted on February 16, 2020 by | Leave a comment

Legionella Control

CDC legionella

Image CDC

In this review the experts at Legionella Control International look at how water temperatures influence legionella growth and how this information can be used to control the risks from the bacteria.

Under certain circumstances Legionella bacteria can lead to serious illness and fatalities in humans. Since Legionella bacteria can exist in man-made water systems, it is imperative to ensure the water is stored, maintained and distributed at temperatures that do not encourage the growth and spread of the bacteria.

There are three temperature ranges that have an influence on the growth and proliferation of Legionella bacteria. We’ll look at each of these in the link above.

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Posted in Contaminated water, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Legionella, Legionnaires’ disease, microbial contamination, Microbiology, Research, Uncategorized, water microbiology, Water Safety

Research – Complex Interactions Between Weather, and Microbial and Physicochemical Water Quality Impact the Likelihood of Detecting Foodborne Pathogens in Agricultural Water

Posted on February 16, 2020 by | Leave a comment

Frontiers

Agricultural water is an important source of foodborne pathogens on produce farms. Managing water-associated risks does not lend itself to one-size-fits-all approaches due to the heterogeneous nature of freshwater environments. To improve our ability to develop location-specific risk management practices, a study was conducted in two produce-growing regions to (i) characterize the relationship between Escherichia coli levels and pathogen presence in agricultural water, and (ii) identify environmental factors associated with pathogen detection. Three AZ and six NY waterways were sampled longitudinally using 10-L grab samples (GS) and 24-h Moore swabs (MS). Regression showed that the likelihood of Salmonella detection (Odds Ratio [OR] = 2.18), and eaeA-stx codetection (OR = 6.49) was significantly greater for MS compared to GS, while the likelihood of detecting L. monocytogenes was not. Regression also showed that eaeA-stx codetection in AZ (OR = 50.2) and NY (OR = 18.4), and Salmonella detection in AZ (OR = 4.4) were significantly associated with E. coli levels, while Salmonella detection in NY was not. Random forest analysis indicated that interactions between environmental factors (e.g., rainfall, temperature, turbidity) (i) were associated with likelihood of pathogen detection and (ii) mediated the relationship between E. coli levels and likelihood of pathogen detection. Our findings suggest that (i) environmental heterogeneity, including interactions between factors, affects microbial water quality, and (ii) E. coli levels alone may not be a suitable indicator of food safety risks. Instead, targeted methods that utilize environmental and microbial data (e.g., models that use turbidity and E. coli levels to predict when there is a high or low risk of surface water being contaminated by pathogens) are needed to assess and mitigate the food safety risks associated with preharvest water use. By identifying environmental factors associated with an increased likelihood of detecting pathogens in agricultural water, this study provides information that (i) can be used to assess when pathogen contamination of agricultural water is likely to occur, and (ii) facilitate development of targeted interventions for individual water sources, providing an alternative to existing one-size-fits-all approaches.

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Posted in E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Listeria, Listeria monocytogenes, microbial contamination, Microbiology, Pathogen, pathogenic, Research, Salmonella, STX 1, STX 2, Uncategorized

Research -An in situ-Synthesized Gene Chip for the Detection of Food-Borne Pathogens on Fresh-Cut Cantaloupe and Lettuce

Posted on February 15, 2020 by | Leave a comment

Frontiers

Fresh foods are vulnerable to foodborne pathogens which cause foodborne illness and endanger people’s life and safety. The rapid detection of foodborne pathogens is crucial for food safety surveillance. An in situ-synthesized gene chip for the detection of foodborne pathogens on fresh-cut fruits and vegetables was developed. The target genes were identified and screened by comparing the specific sequences of Salmonella Typhimurium, Vibrio parahemolyticus, Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli O157:H7 from the National Center for Biotechnology Information database. Tiling array probes were designed to target selected genes in an optimized hybridization system. A total of 141 specific probes were selected from 3,227 hybridization probes, comprising 26 L. monocytogenes, 24 S. aureus, 25 E. coli O157:H7, 20 Salmonella Typhimurium, and 46 V. parahemolyticus probes that are unique to this study. The optimized assay had strong amplification signals and high accuracy. The detection limit for the five target pathogens on fresh-cut cantaloupe and lettuce was approximately 3 log cfu/g without culturing and with a detection time of 24 h. The detection technology established in this study can rapidly detect and monitor the foodborne pathogens on fresh-cut fruits and vegetables throughout the logistical distribution chain, i.e., processing, cleaning, fresh-cutting, packaging, storage, transport, and sale, and represents a valuable technology that support the safety of fresh agricultural products.

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Posted in E.coli, E.coli O157, E.coli O157:H7, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, Listeria, Listeria monocytogenes, microbial contamination, Microbiology, Research, Staphylococcus aureus, Technology, Uncategorized, Vibrio, Vibrio parahaemolyticus

Research – Fate of Listeria on various food contact and noncontact surfaces when treated with bacteriophage

Posted on February 15, 2020 by | Leave a comment

Wiley Online

Study objective was to determine efficacy of a bacteriophage suspension against Listeria spp. when applied to three common types of materials used in food manufacturing facilities. Materials included two food contact materials (stainless steel and polyurethane thermoplastic belting) and one noncontact material (epoxy flooring). Coupons of each material were inoculated with a cocktail containing L. monocytogenes and L. innocua (4 to 5‐log10 CFU/cm2). Two phage concentrations and a control, 0, 2 × 107 and 1 × 108 PFU/cm2 were evaluated. Treated samples were held at 4 or 20°C for 1 and 3 hr to determine the effect of temperature and treatment time. Reductions in Listeria populations ranged from 1.27 to 3.33 log10 CFU/cm2 on stainless steel, from 1.17 to 2.76 log10 CFU/cm2 on polyurethane thermoplastic belting, and from 1.19 to 1.76 log10 CFU/cm2 on epoxy resin flooring. Higher phage concentration (1 × 108 PFU/cm2), longer treatment time (3 hr), and processing area temperature of 20°C showed a greater (p ≤ .05) reduction of Listeria on the stainless‐steel and polyurethane thermoplastic belting coupons. Overall, Listeria reduction by phage treatment occurred on all three materials tested, under all conditions.

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Posted in Bacteriophage, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, Listeria, Listeria monocytogenes, microbial contamination, Microbiology, Research, Uncategorized

Research – New approach to unraveling Clostridium difficile

Posted on February 13, 2020 by | Leave a comment

Science Daily Clostridium_difficile_01

The Clostridium difficile pathogen takes its name from the French word for “difficult.” A bacterium that is known to cause symptoms ranging from diarrhea to life-threatening colon damage, C. difficile is part of a growing epidemic of concern for the elderly and patients on antibiotics.

Outbreaks of C. difficile-infected cases have progressively increased in Western countries, with 29,000 reported deaths per year in the United States alone.

Now, biologists at the University of California San Diego are drawing parallels from newly developed models of the common fruit fly to help lay the foundation for novel therapies to fight the pathogen’s spread. Their report is published in the journal iScience.

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Posted in Clostridium difficile, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, microbial contamination, Microbiology, Research, Uncategorized

Research – Analyzing the differences in antibiotic resistance between the gut and mouth microbiome

Posted on February 13, 2020 by | Leave a comment

Science Daily

The threat of antimicrobial resistance to medication is a global health issue. Recent years have seen a surge in our awareness of resistance genes; and as a result of the prevalence of these genes, antibiotics are becoming less effective at treating microbial infections, such as TB and gonorrhoea.

Although much work has been done analysing the human gut microbiome and its associated genes, little is currently known about these genes in the mouth.

In a paper published today in Nature Communications, academics from King’s College London have taken the first step to examine the antimicrobial resistance potential of the mouth — the oral resistome. As the mouth is the first point of entry for food and many medications, it has the potential to influence the spread of antimicrobial resistance in the human microbiome. Antimicrobial resistance arises when the microbe acquires genes that attempt to avoid or destroy the drugs.

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Posted in Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, microbial contamination, Microbiology, Microbiome, Research, Uncategorized

Scotland – Annual surveillance reports – Salmonella and Campylobacter

Posted on February 12, 2020 by | Leave a comment

HPS

Article: 54/601

The annual surveillance reports for laboratory confirmed cases of Salmonella and Campylobacter in Scotland in 2019 are now available on the Health Protection Scotland (HPS) website.

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Posted in Campylobacter, food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Food Safety, Food Testing, Research, Salmonella, Uncategorized

Research -Microbial composition of Korean kefir and antimicrobial activity of Acetobacter fabarum DH1801

Posted on February 11, 2020 by | Leave a comment

Wiley Online

Kefir is a probiotic dairy product containing multiple species of lactic acid bacteria, acetic acid bacteria, and yeast, with varying microbial composition depending on geographical origin. In the present study, we characterized the acetic acid bacterial population in Korean kefir by next‐generation sequencing‐based community analysis and isolated a novel acetic acid bacterial strain, Acetobacter fabarum DH1801. To evaluate its potential application in the food industry, the antimicrobial activity of A. fabarum DH1801 against seven foodborne pathogens (Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Cronobacter sakazakii, Salmonella Enteritidis, enterotoxigenic Escherichia coli, and Shigella flexneri) was analyzed by growth curve analysis. Remarkably, the culture filtrate of the novel isolate inhibited the growth of all seven pathogenic bacteria in a dose‐dependent manner, which was superior to acetic acid solution of same pH value. Our findings suggest that the A. fabarum DH1801 strain forms a protective barrier during kefir fermentation against contamination by foodborne pathogens.

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Posted in Acetobacter, Cronobacter sakazakii, E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Listeria monocytogenes, microbial contamination, Microbiology, Research, Salmonella, Shigella, Shigella flexneri, Uncategorized