Category Archives: Bacteriophage

Research -Isolation and Characterization of Bacteriophage VA5 against Vibrio alginolyticus

Posted on November 26, 2023 by | Leave a comment

MDPI

Abstract

Bacteriophages, or phages, can be used as natural biological control agents to eliminate pathogenic bacteria during aquatic product cultivation. Samples were collected from seafood aquaculture water and aquaculture environmental sewage, and phage VA5 was isolated using the double-layer agar plate method, with Vibrio alginolyticus as the host bacteria. The purified phage strain was subjected to genome sequencing analysis and morphological observation. The optimal multiplicity of infection (MOI), the one-step growth curve, temperature stability, and pH stability were analyzed. Phage VA5 was observed to have a long tail. Whole-genome sequencing revealed that the genome was circular dsDNA, with 35,866 bp length and 46% G+C content. The optimal MOI was 1, the incubation period was 20 min, the outbreak period was 30 min, and the cleavage amount was 92.26 PFU/cell. The phage showed good activity at −20 °C, 70 °C, and pH 2–10. Moreover, the phage VA5 exhibited significant inhibitory effects on V. alginolyticus-infected shrimp culture. The isolated phage VA5 has a wide range of host bacteria and is a good candidate for biological control of pathogenic bacteria.

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Posted in Bacteriophage, Food Microbiology Research, Phage, Research, Vibrio, Vibrio alginolyticus

Research – Control of Salmonella in Chicken Meat by a Phage Cocktail in Combination with Propionic Acid and Modified Atmosphere Packaging

Posted on November 26, 2023 by | Leave a comment

MDPI

Abstract

Salmonella contamination in poultry meat is an important food safety issue as this pathogen can lead to serious illness and economic losses worldwide. In poultry meat processing, a variety of strong bacteriostatic agents has been introduced for controlling Salmonella including bacteriophages (phages), organic acids, and modified atmosphere packaging (MAP). In our study, two selected phages including vB_SenM_P7 and vB_SenP_P32 were used in combination with propionic acid (PA) and MAP for controlling Salmonella of multiple serovars on chicken meat under storage at 4 °C. The two phages showed strong lytic activity against over 72 serovars of Salmonella tested (25.0 to 80.6%). Phages, vB_SenM_P7 and vB_SenP_P32 showed 40% and 60% survival rates, respectively, after the exposure to temperatures up to 70 °C. Both phages remained active, with nearly 100% survival at a wide range of pH (2 to 12) and 15% NaCl (w/v). The available chlorine up to 0.3% (v/v) led to a phage survival rate of 80–100%. A combination of Salmonella phage cocktail and 0.5% PA could reduce Salmonella counts in vitro by 4 log CFU/mL on day 3 whereas a phage cocktail and 0.25% PA showed a 4-log reduction on day 5 during storage at 4 °C. For the phage treatment alone, a 0.3-log reduction of Salmonella was observed on day 1 of storage at 4 °C. In the chicken meat model, treatment by a phage cocktail and PA at both concentrations in MAP conditions resulted in a complete reduction of Salmonella cells (4–5 log unit/g) on day 2 of storage whereas each single treatment under MAP conditions showed a complete cell reduction on day 4. For the meat sensory evaluation, chicken meat treated with a phage cocktail-PA (0.5%) in MAP condition showed the highest preference scores, suggesting highly acceptability and satisfactory. These findings suggest that a combined treatment using a phage cocktail and PA in MAP conditions effectively control Salmonella in poultry meat during storage at low temperature to improve the quality and safety of food.

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Posted in Bacteriophage, Food Microbiology Research, Food Pathogen, Modified Atmosphere Packaging, Pathogen, pathogenic, Phage, Research, Salmonella

Research – Safety Properties of Escherichia coli O157:H7 Specific Bacteriophages: Recent Advances for Food Safety

Posted on November 5, 2023 by | Leave a comment

MDPI

Abstract

Shiga-toxin-producing Escherichia coli (STEC) is typically detected on food products mainly due to cross-contamination with faecal matter. The serotype O157:H7 has been of major public health concern due to the severity of illness caused, prevalence, and management. In the food chain, the main methods of controlling contamination by foodborne pathogens often involve the application of antimicrobial agents, which are now becoming less efficient. There is a growing need for the development of new approaches to combat these pathogens, especially those that harbour antimicrobial resistant and virulent determinants. Strategies to also limit their presence on food contact surfaces and food matrices are needed to prevent their transmission. Recent studies have revealed that bacteriophages are useful non-antibiotic options for biocontrol of E. coli O157:H7 in both animals and humans. Phage biocontrol can significantly reduce E. coli O157:H7, thereby improving food safety. However, before being certified as potential biocontrol agents, the safety of the phage candidates must be resolved to satisfy regulatory standards, particularly regarding phage resistance, antigenic properties, and toxigenic properties. In this review, we provide a general description of the main virulence elements of E. coli O157:H7 and present detailed reports that support the proposals that phages infecting E. coli O157:H7 are potential biocontrol agents. This paper also outlines the mechanism of E. coli O157:H7 resistance to phages and the safety concerns associated with the use of phages as a biocontrol.

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Posted in Bacteriophage, E.coli O157, E.coli O157:H7, Food Microbiology Research, Food Technology, Hurdle Technology, Phage, Research, STEC, STEC E.coli, Technology

Research – Studying bacteriophage therapy in chickens

Posted on September 11, 2023 by | Leave a comment

DVM360

Salmonella Campylobacter

Fowl typhoid (FT) is among the most significant poultry bacterial diseases worldwide, mostly affecting developing countries.1 The causal agent of FT is Salmonella enterica Gallinarum. Although S enterica Gallinarum is egg-transmitted and produces lesions in chicks and poults, there is a much greater tendency to spread among growing or mature flocks. Mortality in young birds is possible but tends to be higher in older birds.2

In a poster presentation at the 2023 World Anti-Microbial Resistance Congress in Philadelphia, Pennsylvania, researchers from Purdue University in West Lafayette, Indiana, and the University of Veterinary and Animal Sciences (UVAS) Lahore, Pakistan, stated that, “Antibiotics are often used to prevent or control fowl typhoid; however, such practices contribute to the continually global challenge of antibiotic resistance.”1

“In previous studies, we developed a polyphage prototype that significantly reduced Salmonella Gallinarum in experimentally challenged chickens. Here, we evaluated the pact of treatment with the polyphage prototype on microbial communities surrounding the targeted bacteria.”1

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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, Phage, Salmonella, Salmonella in Chicken

Research- Optimization of the Use of a Commercial Phage-Based Product as a Control Strategy of Listeria monocytogenes in the Fresh-Cut Industry

Posted on August 28, 2023 by | Leave a comment

MDPI

Abstract

A commercial phage biocontrol for reducing Listeria monocytogenes has been described as an effective tool for improving fresh produce safety. Critical challenges in the phage application must be overcome for the industrial application. The validation studies were performed in two processing lines of two industry collaborators in Spain and Denmark, using shredded iceberg lettuce as the ready-to-eat (RTE), high process volume product. The biocontrol treatment optimized in lab-scale trials for the application of PhageGuard ListexTM was confirmed in industrial settings by four tests, two in Spain and two in Denmark. Results showed that the method of application that included the device and the processing operation step was appropriate for the proper application. The proper dose of Phage Guard ListexTM was reached in shredded iceberg lettuce and the surface was adequately covered for the successful application of phages. There was no impact on the headspace gas composition (CO2 and O2 levels), nor on the color when untreated and treated samples were compared. The post-process treatment with PhageGuard ListexTM did not cause any detrimental impact on the sensory quality, including flavor, texture, browning, spoilage, and visual appearance over the shelf-life as the phage solution was applied as a fine, mist solution.

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

Research – The brink of a phage paradigm shift in the EU?

Posted on July 22, 2023 by | Leave a comment

Poultry World

We might be on the brink of a phage paradigm shift in the European Union. This was the view of various experts during an online webinar on 11 July organised by PhageEU, a coalition of stakeholders representing phages in industry, the scientific community and civil society.

A feed additive based on phage technology could be authorised by the European Commission in the near future, they agreed, adding that this would be a template for the development of ground-breaking phage products in poultry and other food-producing animals.

The webinar was an opportunity to discuss technical challenges to designing bacteriophage products, the regulatory hurdles in Europe for this new product category as well as to analyse the recent political debate in the EU institutions and the future outlook.

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

Research – Bacteriophages for the Targeted Control of Foodborne Pathogens

Posted on July 19, 2023 by | Leave a comment

MDPI

Abstract

Foodborne illness is exacerbated by novel and emerging pathotypes, persistent contamination, antimicrobial resistance, an ever-changing environment, and the complexity of food production systems. Sporadic and outbreak events of common foodborne pathogens like Shiga toxigenic E. coli (STEC), Salmonella, Campylobacter, and Listeria monocytogenes are increasingly identified. Methods of controlling human infections linked with food products are essential to improve food safety and public health and to avoid economic losses associated with contaminated food product recalls and litigations. Bacteriophages (phages) are an attractive additional weapon in the ongoing search for preventative measures to improve food safety and public health. However, like all other antimicrobial interventions that are being employed in food production systems, phages are not a panacea to all food safety challenges. Therefore, while phage-based biocontrol can be promising in combating foodborne pathogens, their antibacterial spectrum is generally narrower than most antibiotics. The emergence of phage-insensitive single-cell variants and the formulation of effective cocktails are some of the challenges faced by phage-based biocontrol methods. This review examines phage-based applications at critical control points in food production systems with an emphasis on when and where they can be successfully applied at production and processing levels. Shortcomings associated with phage-based control measures are outlined together with strategies that can be applied to improve phage utility for current and future applications in food safety.

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Posted in Bacteriophage, Campylobacter, campylobacter coli, Campylobacter jejuni, Decontamination Microbial, Food Illness, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Foodborne Illness, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Salmonella, STEC, STEC E.coli

Research – A Highly Effective Bacteriophage-1252 to Control Multiple Serovars of Salmonella enterica

Posted on February 19, 2023 by | Leave a comment

MDPI

Abstract

Salmonella enterica (S. enterica) is the most common foodborne pathogen worldwide, leading to massive economic loss and a significant burden on the healthcare system. The primary source of S. enterica remains contaminated or undercooked poultry products. Considering the number of foodborne illnesses with multiple antibiotic resistant S. enterica, new controlling approaches are necessary. Bacteriophage (phage) therapies have emerged as a promising alternative to controlling bacterial pathogens. However, the limitation on the lysis ability of most phages is their species-specificity to the bacterium. S. enterica has various serovars, and several major serovars are involved in gastrointestinal diseases in the USA. In this study, Salmonella bacteriophage-1252 (phage-1252) was isolated and found to have the highest lytic activity against multiple serovars of S. enterica, including Typhimurium, Enteritidis, Newport, Heidelberg, Kentucky, and Gallinarum. Whole-genome sequencing analysis revealed phage-1252 is a novel phage strain that belongs to the genus Duplodnaviria in the Myoviridae family, and consists of a 244,421 bp dsDNA, with a G + C content of 48.51%. Its plaque diameters are approximately 2.5 mm to 0.5 mm on the agar plate. It inhibited Salmonella Enteritidis growth after 6 h. The growth curve showed that the latent and rise periods were approximately 40 min and 30 min, respectively. The burst size was estimated to be 56 PFU/cell. It can stabilize and maintain original activity between 4 °C and 55 °C for 1 h. These results indicate that phage-1252 is a promising candidate for controlling multiple S. enterica serovars in food production.

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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, Phage, Salmonella

Research – Natural Killers: Opportunities and Challenges for the Use of Bacteriophages in Microbial Food Safety from the One Health Perspective

Posted on February 2, 2023 by | Leave a comment

MDPI

Abstract

Ingestion of food or water contaminated with pathogenic bacteria may cause serious diseases. The One Health approach may help to ensure food safety by anticipating, preventing, detecting, and controlling diseases that spread between animals, humans, and the environment. This concept pays special attention to the increasing spread and dissemination of antibiotic-resistant bacteria, which are considered one of the most important environment-related human and animal health hazards. In this context, the development of innovative, versatile, and effective alternatives to control bacterial infections in order to assure comprehensive food microbial safety is becoming an urgent issue. Bacteriophages (phages), viruses of bacteria, have gained significance in the last years due to the request for new effective antimicrobials for the treatment of bacterial diseases, along with many other applications, including biotechnology and food safety. This manuscript reviews the application of phages in order to prevent food- and water-borne diseases from a One Health perspective. Regarding the necessary decrease in the use of antibiotics, results taken from the literature indicate that phages are also promising tools to help to address this issue. To assist future phage-based real applications, the pending issues and main challenges to be addressed shortly by future studies are also taken into account.

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Posted in Bacteriophage, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Safety, Food Safety Management, food safety training, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Phage

Research – UK to tackle Salmonella risks in raw pet food

Posted on January 17, 2023 by | Leave a comment

Pet Food Processing

The UK Food Safety Research Network, hosted by Quadram Institute, announced that six food safety projects will receive between £30,000 to £62,000 (roughly $36,544 USD to $73,089 USD) in funds. One of the projects aims to improve food safety of raw pet food formulas.

All six projects involve academic researchers collaborating with commercial companies and/or government agencies within the human and pet food sectors to establish solutions to common food safety issues.

The raw pet food project involves using bacteriophages to help decrease Salmonella contamination in raw pet food products. According to the Quadram Institute, raw pet foods are growing in popularity throughout the United Kingdom as pet parents seek non-processed diets to improve their pets’ health. However, raw pet foods can carry higher risk of contamination compared to their cooked counterparts.

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Posted in Bacteria, Bacteriophage, Food Micro Blog, Food Microbiology Blog, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Pet Food Salmonella, Pet Food Testing, raw pet food, Salmonella