Category Archives: Food Microbiology Research

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 -Improvement of Microbial Quality, Physicochemical Properties, Fatty Acids Profile, and Shelf Life of Basa (Pangasius bocourti) Fillets during Chilling Storage Using Pepsin, Rosemary Oil, and Citric Acid

Posted on November 26, 2023 by | Leave a comment

MDPI

Abstract

Meat discoloration, lipid oxidation, and undesirable texture are inevitable phenomena in basa fish fillets during storage, which in turn limits their exportation as well as decreases consumer acceptability. In addition, increasing consumers’ requirements for high-quality, minimally processed, and ready-to-cook fish fillets with an extended shelf-life is a great challenge, particularly with lifestyle changes. Accordingly, this study aimed to improve the quality, lipid stability, fatty acid profile, and lipid nutritional quality indices (LNQI) of basa fish fillets during chilling storage at 4 °C for 15 days using pepsin enzyme (E, 0.1%), rosemary oil (R, 0.5%), citric acid (CA, 0.5%), and their combination (0.1% E + 0.5% R; 0.1% E + 0.5% CA; and 0.1% E + 0.5% R + 0.5% CA). Our results revealed that all treated samples exhibited a significant increase in protein content, a significant decrease in fat content, and a marked reduction in pH, total volatile base nitrogen (TVBN), thiobarbituric acid (TBA), free fatty acids, and shear force (SF) values in comparison to control ones. Moreover, significant improvements in sensory scores, color stability, fatty acid profile, LNQI, and microbial quality of all treated samples were observed. Such findings were more pronounced in samples treated with a mixture of pepsin, rosemary, and citric acid (TVBN: 2.04 vs. 6.52 mg%; TBA: 0.40 vs. 2.68 mg malonaldehyde/Kg; and SF: 8.58 vs. 19.51 Kgf). Based on the obtained results, there was an extension for the shelf life of all treated basa fish fillet samples, especially in samples treated with a mixture of pepsin, rosemary, and citric acids when compared with the control samples (˃15 days versus 10 days). Additionally, eucalyptol, camphor, isoborneol, and α-pinene are the main components of rosemary, with great antioxidant and antimicrobial activity. In conclusion, the mixture of pepsin, rosemary, and citric acid can be applied easily in the seafood industry and at the household level to provide ready-to-cook fish fillets of high quality with great health benefits.

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

Research – Microbial Pathogens in Aquaponics Potentially Hazardous for Human Health

Posted on November 25, 2023 by | Leave a comment

MDPI

Abstract

The union of aquaculture and hydroponics is named aquaponics—a system where microorganisms, fish and plants coexist in a water environment. Bacteria are essential in processes which are fundamental for the functioning and equilibrium of aquaponic systems. Such processes are nitrification, extraction of various macro- and micronutrients from the feed leftovers and feces, etc. However, in aquaponics there are not only beneficial, but also potentially hazardous microorganisms of fish, human, and plant origin. It is important to establish the presence of human pathogens, their way of entering the aforementioned systems, and their control in order to assess the risk to human health when consuming plants and fish grown in aquaponics. Literature analysis shows that aquaponic bacteria and yeasts are mainly pathogenic to fish and humans but rarely to plants, while most of the molds are pathogenic to humans, plants, and fish. Since the various human pathogenic bacteria and fungi found in aquaponics enter the water when proper hygiene practices are not applied and followed, if these requirements are met, aquaponic systems are a good choice for growing healthy fish and plants safe for human consumption. However, many of the aquaponic pathogens are listed in the WHO list of drug-resistant bacteria for which new antibiotics are urgently needed, making disease control by antibiotics a real challenge. Because pathogen control by conventional physical methods, chemical methods, and antibiotic treatment is potentially harmful to humans, fish, plants, and beneficial microorganisms, a biological control with antagonistic microorganisms, phytotherapy, bacteriophage therapy, and nanomedicine are potential alternatives to these methods.

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Posted in Food Microbiology Research, Food Pathogen, Pathogen, pathogenic, Research

Research – Qatar team identifies way to inhibit mycotoxin growth in fish feed

Posted on November 25, 2023 by | Leave a comment

Feed Navigator

Qatar based researchers say the findings of their study indicate that aquaculture feed imports from some Asian and European countries can be contaminated with moderate levels of mycotoxins.

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Posted in Animal Feed Mould/Mold, Food Microbiology Research, mold, Mold Toxin, Mould/Mold, Mycotoxin, Research

Research – High Prevalence of Multidrug-Resistant, Biofilm-Forming Virulent Clostridium perfringens in Broiler Chicken Retail Points in Northeast India

Posted on November 25, 2023 by | Leave a comment

MDPI

Abstract

In light of the significant public health and food safety implications associated with Clostridium perfringens, this study aimed to isolate and characterize C. perfringens in samples obtained from broiler chicken retail points in Meghalaya, northeastern India. A total of 280 samples comprising meat, intestinal contents, water, and hand swabs were processed to detect contamination by C. perfringens. The isolates were subjected to toxinotyping, antimicrobial susceptibility testing, and biofilm-forming ability test. The overall occurrence of C. perfringens was 22.5% (17.74–27.85, 95% CI) with the highest recovery from intestine samples (31%; 22.13–41.03, 95% CI), followed by meat (23%, 15.17–32.49, 95% CI) and water samples (18%, 8.58–31.44, 95% CI). Type A was the predominant toxinotype (71.43%, 58.65–82.11, 95% CI), followed by Type A with beta2 toxin (17.46%, 9.05–29.10, 95% CI), Type C (7.94%, 2.63–17.56, 95% CI), and Type C with beta2 toxin (3.17%, 0.39–11.0, 95% CI). Nearly all (95.24%) isolates were multidrug resistant and 68.25% were biofilm formers. The predominance of multidrug-resistant and virulent Type A and Type C C. perfringens in retail broiler meat and intestines in the tribal-dominated northeastern region of India is of great concern from food safety and public health perspectives.

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Posted in Clostridium, Clostridium perfringens, Food Microbiology Research, Multi Drug Resistant, Research

Research – Salmonella Infection in Poultry: A Review on the Pathogen and Control Strategies

Posted on November 25, 2023 by | Leave a comment

MDPI

Abstract

Salmonella is the leading cause of food-borne zoonotic disease worldwide. Non-typhoidal Salmonella serotypes are the primary etiological agents associated with salmonellosis in poultry. Contaminated poultry eggs and meat products are the major sources of human Salmonella infection. Horizontal and vertical transmission are the primary routes of infection in chickens. The principal virulence genes linked to Salmonella pathogenesis in poultry are located in Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2). Cell-mediated and humoral immune responses are involved in the defense against Salmonella invasion in poultry. Vaccination of chickens and supplementation of feed additives like prebiotics, probiotics, postbiotics, synbiotics, and bacteriophages are currently being used to mitigate the Salmonella load in poultry. Despite the existence of various control measures, there is still a need for a broad, safe, and well-defined strategy that can confer long-term protection from Salmonella in poultry flocks. This review examines the current knowledge on the etiology, transmission, cell wall structure, nomenclature, pathogenesis, immune response, and efficacy of preventative approaches to Salmonella.

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Posted in Animal Feed Salmonella, Food Microbiology Research, Research, Salmonella, Salmonella in Chicken

Research – Sage Essential Oil as an Antimicrobial Agent against Salmonella enterica during Beef Sous Vide Storage

Posted on November 25, 2023 by | Leave a comment

MDPI

Abstract

Sous-vide is a process comprising vacuum-sealing food, heating it to the desired temperature, and circulating it in a water bath in a sous vide machine. This cooking technique is increasingly common in homes and catering establishments due to its simplicity and affordability. However, manufacturers and chef’s recommendations for low-temperature and long-term sous-vide cooking in media raise food safety concerns, particularly when preparing beef tenderloin. In this study, Salmonella enterica was found to be inactivated by heat and sage essential oil (EO) in beef samples from musculus psoas major that had been sous vide processed. To determine whether heat treatment was likely to increase the sous vide efficiency, S. enterica and sage EO were mixed. After being vacuum-packed and injected with S. enterica, the samples were cooked at 50–65 °C through the sous vide technique for the prescribed time. On days 1, 3, and 6, the amounts of S. enterica, total bacteria, and coliform bacteria were measured in the control and treated groups of beef processed sous vide. Mass spectrometry was used to identify bacterial isolates on different days. On each day that was measured, a higher number of all the microbiota was found in the samples exposed to 50 °C for 5 min. The most frequently isolated microorganisms from both groups of samples were Pseudomonas fragi (17%), Pseudomonas cedrina (8%), and Proteus vulgaris (8%); in the treated group, also S. enterica (21%), Pseudomonas fragi (13%), and Pseudomonas veronii (6%). After the heat treatment of samples at 65 °C for 20 min, the total count of bacteria and coliform bacteria was zero. It has been shown that adding sage essential oil (EO) in combination with sous vide processing technique leads to the stabilization and safety of beef tenderloin.

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

Number of food poisoning patients in Japan expected to rise for 1st time in 3 yrs

Posted on November 24, 2023 by | Leave a comment

Mainichi

TOKYO — Japan’s health ministry is calling for caution as the number of food poisoning patients in the country is expected to increase for the first time in three years, with the risk existing even in winter.

There has been a spate of food poisoning patients due to the easing of measures against coronavirus infections. Some outbreaks have occurred in groups of several hundred people after eating bento boxed lunches or “nagashi-somen” — noodles carried by water in flumes of bamboo so that diners can pluck them out with their chopsticks to eat.

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Posted in Food Illness, Food Microbiology Research, Food Poisoning, Foodborne Illness, Illness, Poisoning, Research

Research – Foodborne botulism outbreak involving different nationalities during the Rugby World Cup: critical role of credit card data and rapid international cooperation, France, September 2023

Posted on November 24, 2023 by | Leave a comment

Eurosurveillance

An unprecedented outbreak of 15 cases (including one death) of foodborne botulism occurred in Bordeaux, France, in September 2023 during the Rugby World Cup. Here we describe the national and international outbreak investigation using credit card data and control measures taken.

On 10 September 2023, the Bordeaux University Hospital reported three suspected cases of botulism to the local public health authorities [1]. All suspected cases had visited the same restaurant (Restaurant A) in Bordeaux on different dates and reported consumption of canned marinated sardines. The sardines were part of a batch made by Restaurant A on 1 September 2023 and served between 1 and 10 September. Cases were of different nationalities. In the previous days, the city had hosted two international rugby games as part of the Rugby World Cup attended by a large number of international visitors. An investigation was initiated to identify and contact persons visiting restaurant A and to contact public health agencies of countries whose citizens were affected by the outbreak.

Considering the severity of botulism and the urgency of control measures to stop the outbreak, an active search for persons who had consumed the sardines was performed by using data retrieved from credit card receipts of restaurant A.

A suspected case of botulism was defined as a person with symptoms compatible with botulism (oculomotor palsy, mydriasis, ptosis, dysphagia, nausea, vomiting, diarrhoea), living or visiting the Bordeaux area and visiting Restaurant A between 1 and 10 September 2023. A confirmed case was defined as detection of type B botulinum neurotoxins (BoNT) in stool and/or serum samples and/or detection of type B  in stools from a suspected case.

By screening meal orders and credit card receipts of Restaurant A, we identified 29 customers who had ordered canned sardines (Figure 1). Among these, 12 had already been identified as suspected cases, 14 were contacted by the French or British health authorities and were considered non-cases as they did not present any symptoms and three were symptomatic British citizens who were urgently referred to an emergency care in the United Kingdom (UK) on 13 September where they received botulinum antitoxin.

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Posted in Clostridium, Clostridium botulinum, Death, food death, Food Illness, Food Microbiology Research, Food Poisoning Death, Foodborne Illness, Foodborne Illness Death, Illness, Research