Category Archives: Bacteriophage

Research – Cross-Contamination to Surfaces in Consumer Kitchens with MS2 as a Tracer Organism in Ground Turkey Patties

Posted on January 8, 2023 by | Leave a comment

Journal of Food Protection

ABSTRACT

It is estimated that one in five cases of foodborne illnesses is acquired in the home. However, how pathogens move throughout a kitchen environment when consumers are preparing food is not well characterized. The purpose of this study was to determine the prevalence and degree of cross-contamination across a variety of kitchen surfaces during a consumer meal preparation event. Consumers (n = 371) prepared a meal consisting of turkey patties containing the bacteriophage MS2 as a tracer organism and a ready-to-eat lettuce salad. Half were shown a video on proper thermometer use before the trial. After meal preparation, environmental sampling and detection were performed to assess cross-contamination with MS2. For most surfaces, positivity did not exceed 20%, with the exception of spice containers, for which 48% of the samples showed evidence of MS2 cross-contamination. Spice containers also had the highest MS2 concentrations, at a mean exceeding 6 log viral genome equivalent copies per surface. The high level of MS2 on spice containers drove the significant differences between surfaces, suggesting the significance of spice containers as a vehicle for cross-contamination, despite the absence of previous reports to this effect. The thermometer safety intervention did not affect cross-contamination. The efficiency of MS2 transfer, when expressed as a percentage, was relatively low, ranging from an average of 0.002 to 0.07%. Quantitative risk assessment work using these data would aid in further understanding the significance of cross-contamination frequency and efficiency. Overall, these data will help create more targeted consumer messaging to better influence consumer cross-contamination behaviors.

HIGHLIGHTS
  • Forty-eight percent of spice containers sampled showed evidence of MS2 cross-contamination.
  • Spice containers had the highest MS2 concentrations across kitchen surfaces.
  • Spice containers may be a key vehicle for cross-contamination.
  • The thermometer safety intervention did not affect cross-contamination.
  • The efficiency of MS2 transfer was relatively low, ranging from 0.002 to 0.07%.

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

Research – Spraying an army of bacteria-eating viruses can save us from food poisoning

Posted on December 27, 2022 by | Leave a comment

Interesting Engineering

Every year more than 40 million people in the U.S. suffer from foodborne illnesses caused by bacteria, viruses, and various other types of pathogens. Food contamination is often underestimated, but it is responsible for 420,000 deaths annually. This number represents more people than the entire population of Iceland.

After being produced on a farm, food passes through a lot of channels before it makes it to our platter. Preventing it from contamination is almost impossible. However, a team of researchers from McMaster University in Ontario has figured out a way to free food from disease-causing bacteria before it goes into your stomach, according to a press release.

They have developed a food decontamination spray that employs food-safe microscopic beads containing bacteriophages (viruses that kill bacteria). The researchers claim, during the study, they were able to free lettuce and meat from E. coli 0157, a common food-borne pathogen that infects the human intestine and causes health issues such as diarrhea. 

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Posted in Bacteriophage, Decontamination Microbial, E.coli O157, E.coli O157:H7, Food Illness, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Foodborne Illness, Illness, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, STEC, STEC E.coli

Research – Antimicrobial Phage Spray Effective Against Foodborne Bacteria, Including Multidrug Resistant E. Coli

Posted on December 24, 2022 by | Leave a comment

Food Safety.Com

Researchers at McMaster University have developed a new, highly effective tool to mitigate bacterial contamination of foods, including pathogens displaying antimicrobial resistance (AMR). The technology involves the application of bacteriophages (phages)—benign viruses that eat bacteria—to goods in the form of microgels.

Phages are natural predators to bacteria, and because phages attack bacteria in a highly targeted manner, they can be used in food and agriculture without disturbing the balance of microbial communities. Phage products have been approved by the US Food and Drug Administration (FDA) for controlling dangerous bacterial contaminants such as Escherichia coli in food products. Though they do not affect the taste, texture, and nutritional quality of foods, phages are not widely used by industry due to challenges with delivery and stability of phage products.

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Posted in antimicrobial resistance, Bacteriophage, Decontamination Microbial, E.coli, FDA, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Uncategorized

Research -Application of a novel phage ZPAH7 for controlling multidrug-resistant Aeromonas hydrophila on lettuce and reducing biofilms

Posted on November 27, 2022 by | Leave a comment

Science Direct

Abstract

Aeromonas hydrophila is an important pathogenic bacterium that causes foodborne illness worldwide. In this study, virulent phages from the sediment of a fish farm were propagated and isolated on a multidrug-resistant strain of A. hydrophila, ZYAH75. One phage, designated as ZPAH7, featured a unique turbid halo around a clear plaque on the bacterial lawn (indicative of potential depolymerase activity), and was selected for further analysis. ZPAH7 was classified as podophage by morphological and genomic methods. Further comparisons of genome nucleotide similarity, ratios of homologous proteins and phylogenetic relatedness among the terminase large subunit and major capsid proteins of similar phage deposited in GENBANK, led us to propose a new genus, ZPAH7virus, in the Autographivirinae subfamily of Podoviridae. ZPAH7 had an adsorption rate of 79% in 5 min, an eclipse period of 15 min, a latent period of 25 min, and a burst size of 148 ± 9 PFU/cell. Antimicrobial application experiments showed that ZPAH7 lead to significantly reduction on A. hydrophila on lettuce. Additionally, ZPAH7 was able to inhibit biofilm formation, as well as degrade and kill bacteria in established biofilms. Furthermore, lytic activity of ZPAH7 remained stable across a wide range of temperatures and pH measurements. These results suggest ZPAH7 could be used as a potential biological control agent against A. hydrophila on food and/or biofilms on food contact surfaces.

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Posted in Aeromonas, Bacteriophage, Biofilm, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Research

Research – Bacteriophage cocktail shows promise against Vibrio outbreaks in shrimp farms

Posted on October 23, 2022 by | Leave a comment

The Fish Site

Food Illness

Researchers from the Biological Research Center of the Northwest, the Autonomous University of Nuevo León, the Food and Development Research Center AC and the University of Girona evaluated the protective effects of a cocktail of bacteriophages in L. vannamei post larvae against Vibrio bacteria. The scientists found that treating the PLs with bacteriophages kept Vibrio infections at bay and reduced their concentrations in culture water – without harming the surrounding bacterial communities.

Vibrio populations and bacteriophages

Vibrio bacteria are widely disseminated in ocean environments and several Vibrio species are responsible for disease outbreaks in marine animals – especially penaeid shrimp, different fish species and molluscs. Some strains of V. harveyi and V. campbellii have been implicated in disease outbreaks in shrimp hatcheries and grow-out facilities around the world. They’ve also been associated with coral infections.

“We used culture-dependent and culture-independent approaches to explore their effects on bacterial communities associated with shrimp post larvae,” the researchers said. According to the results of the study, administering the phage cocktail drastically reduced Vibrio counts in both in vitro and in vivo environments.

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Posted in Bacteriophage, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Research, Vibrio, Water Safety

Research – Efficacy of Repeated Applications of Bacteriophages on Salmonella enterica-Infected Alfalfa Sprouts during Germination

Posted on October 8, 2022 by | Leave a comment

MDPI

Nontyphoidal Salmonella enterica is one of the leading pathogens for foodborne outbreaks in a multitude of food commodities, including alfalfa sprouts, which are commonly consumed raw. The food industry has commonly used chlorinated washes, but such methods may not be perceived as natural; this can be a detriment as a large portion of sprouts are designated for the organic market. A natural and affordable antimicrobial method that has been acquiring popularity is the use of bacteriophages. This study compared the efficacy of repeated daily applications and a single application of two separate bacteriophage cocktails (SE14, SE20, SF6 and SE14, SF5, SF6) against four Salmonella enterica (S. enterica) strains on germinating alfalfa sprout seeds from days 0 to 7. The results show S. Enteritidis to be the most susceptible to both cocktails with ~2.5 log CFU/mL decrease on day 0 with cocktail SE14, SF5, and SF6. S. enterica populations on all strains continued to grow even with repeated daily bacteriophage applications but in a significantly decreased rate (p < 0.05) compared with a single bacteriophage application. The extent of the reduction was dependent on the S. enterica strain, but the results do show benefits to using repeated bacteriophage applications during sprout germination to reduce S. enterica populations compared with a single bacteriophage application.

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Posted in Bacteriophage, food bourne outbreak, food contamination, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, foodborne outbreak, foodbourne outbreak, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, outbreak, Pathogen, pathogenic, Research, Salmonella

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 – Novel Salmonella Phage, vB_Sen_STGO-35-1, Characterization and Evaluation in Chicken Meat

Posted on March 20, 2022 by | Leave a comment

MDPI

Salmonellosis is one of the most frequently reported zoonotic foodborne diseases worldwide, and poultry is the most important reservoir of Salmonella enterica serovar Enteritidis. The use of lytic bacteriophages (phages) to reduce foodborne pathogens has emerged as a promising biocontrol intervention for Salmonella spp. Here, we describe and evaluate the newly isolated Salmonella phage STGO-35-1, including: (i) genomic and phenotypic characterization, (ii) an analysis of the reduction of Salmonella in chicken meat, and (iii) genome plasticity testing. Phage STGO-35-1 represents an unclassified siphovirus, with a length of 47,483 bp, a G + C content of 46.5%, a headful strategy of packaging, and a virulent lifestyle. Phage STGO-35-1 reduced S. Enteritidis counts in chicken meat by 2.5 orders of magnitude at 4 °C. We identified two receptor-binding proteins with affinity to LPS, and their encoding genes showed plasticity during an exposure assay. Phenotypic, proteomic, and genomic characteristics of STGO-35-1, as well as the Salmonella reduction in chicken meat, support the potential use of STGO-35-1 as a targeted biocontrol agent against S. Enteritidis in chicken meat. Additionally, computational analysis and a short exposure time assay allowed us to predict the plasticity of genes encoding putative receptor-binding proteins.

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Posted in Bacteriophage, Decontamination Microbial, 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, Salmonella, Technology

Research – Uses of Bacteriophages as Bacterial Control Tools and Environmental Safety Indicators

Posted on December 2, 2021 by | Leave a comment

Frontiers in Microbiology

Bacteriophages are bacterial-specific viruses and the most abundant biological form on Earth. Each bacterial species possesses one or multiple bacteriophages and the specificity of infection makes them a promising alternative for bacterial control and environmental safety, as a biotechnological tool against pathogenic bacteria, including those resistant to antibiotics. This application can be either directly into foods and food-related environments as biocontrol agents of biofilm formation. In addition, bacteriophages are used for microbial source-tracking and as fecal indicators. The present review will focus on the uses of bacteriophages like bacterial control tools, environmental safety indicators as well as on their contribution to bacterial control in human, animal, and environmental health.

Introduction

Bacteriophages, also known as phages, are prokaryotes viruses, being the most abundant life form, present in all environments and the predominant entities in the sea (Boehme, 1993; Suttle, 2005). Several studies have demonstrated a 1:5 relative abundance between bacteria and bacteriophage (Fuhrman, 1999; Balter, 2000; Rohwer, 2003). They were discovered independently by Twort (1915), who isolated them from Staphylococcus spp., and from patients with dysentery. D’Herelle (1926) described bacteriophage as a virus that has the capability to parasitize bacteria (Twort, 1915; Delbruck, 1942). Bacteriophages vary greatly in morphology and replicative characteristics, containing either RNA or DNA, being these parameters currently used by the International Committee on Taxonomy of Viruses (ICTV) for bacteriophage classification (King et al., 2012; Table 1). However, the identification of bacteriophages is difficult since there are no universally conserved markers, unlike e.g., the bacterial 16S rRNA gene (Paul et al., 2002), with only minor parts of bacteriophage genomes being used to determine family specific makers, such as the viral capsid g20 of T4 (Fuller et al., 1998; Marston and Sallee, 2003; Sullivan et al., 2008).

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Posted in Bacteriophage, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Staphylococcus aureus, Technology

Research – Reduction of Salmonella enterica in Turkey breast slices kept under aerobic and vacuum conditions by application of lactic acid, a bacteriophage, and ultrasound

Posted on August 19, 2021 by | Leave a comment

Wiley Online

The effects of different antimicrobial applications against Salmonella enterica subs. enterica DSM 18522 strain in turkey breast slices kept under either aerobic or anaerobic-vacuum conditions for different keeping times of 30 min and 6 hr at 4°C were evaluated. In this study, it was aimed to compare chemical (lactic acid, 3%), biopreservation (bacteriophage Felix O1, 1 × 108 pfu/ml), and physical (ultrasound, 20 kHz) antimicrobial applications in reducing a high initial S. enterica DSM 18522 count (~6 log cfu/g) in turkey breast slices at different conditions. The highest reduction in S. enterica DSM 18522 counts (1.62 log units) was observed in turkey breast slices kept under aerobic condition for 6 hr after being treated with lactic acid. The bacteriophage application significantly (p < .05) reduced S. enterica DSM 18522 counts 1.22 and 1.41 log cfu/g in turkey breast slices that kept under aerobic and anaerobic-vacuum conditions for 30 min, respectively. There was no significant effect of keeping time under aerobic or anaerobic-vacuum conditions on S. enterica DSM 18522 counts in turkey breast slices treated with bacteriophage or ultrasound. However, the reduction of S. enterica DSM 18522 counts in turkey breast slices treated with lactic acid increased with keeping time under aerobic or anaerobic-vacuum conditions. Regardless of keeping conditions, the lowest reductions in S. enterica DSM 18522 counts were detected in turkey breast slices treated with ultrasound. The results of this study show that lactic acid and bacteriophage applications are effective in reducing S. enterica DSM 18522 counts in turkey breast slices.

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Posted in Bacteriophage, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, lactic acid bacteria, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Salmonella