Category Archives: Food Microbiology Research

Research – Effects of UV-C Irradiation and Vacuum Sealing on the Shelf-Life of Beef, Chicken and Salmon Fillets

Posted on February 2, 2023 by | Leave a comment

MDPI

Abstract

One-third of the world’s food supply is lost, with meat being a major contributor to this loss. Globally, around 23% of all meat and 35% of all seafood products are lost or wasted. Meats and seafood products are susceptible to microbial spoilage during processing, storage, and distribution, where microbial contamination causes significant losses throughout the supply chain. This study examined the efficacy of UV-C irradiation and vacuum-sealing in preventing microbiological deterioration in beef, chicken, and salmon fillets. The samples were sterilized using a constant UV-C irradiation dose of 360 J/m2 and stored under a reduced pressure of 40 kPa. A microbiological analysis was conducted daily to examine the microbial contamination, which included counting the colonies of Pseudomonas spp., aerobic bacteria, lactic acid bacteria (LAB), Salmonella, and Escherichia coli, as well as monitoring the increase in pH levels. The results demonstrated a statistically significant difference (p > 0.05) in the aerobic bacteria counts between the storage conditions and storage days in all samples, which is a primary indicator of microbial spoilage. In contrast, the differences varied in the Pseudomonas spp. and LAB counts between the storage conditions and storage days, and there was no significant difference (p < 0.05) in the pH levels between the storage conditions. The results indicate that the combination of UV-C irradiation and vacuum sealing effectively inhibits microbial growth and extends the shelf-life of beef, chicken, and salmon fillets by 66.6%.

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Posted in E.coli, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, LAB, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Pseudomonas, Salmonella, UV Microbiology, UV-C

Research – Post-Cooking Growth and Survival of Bacillus cereus Spores in Rice and Their Enzymatic Activities Leading to Food Spoilage Potential

Posted on February 2, 2023 by | Leave a comment

MDPI

Abstract

Bacillus cereus strains vary in their heat resistance, post-processing survival and growth capacity in foods. Hence, this study was carried out to determine the effect of cooking on the survival and growth of eight B. cereus spores in rice at different temperatures in terms of their toxigenic profiles and extracellular enzyme activity. Samples of rice inoculated with different B. cereus spores were cooked and stored at 4 °C, 25 °C and 30 °C for up to 7 days, 48 h and 24 h, respectively. Out of eight B. cereus strains, four and three spore strains were able to grow at 30 °C and 25 °C post-cooking, respectively. Rapid growth was observed after a minimum of 6 h of incubation at 30 °C. All strains possessed proteolytic activity, whereas lipolytic and amylolytic activities were exhibited by 50% and 12.5% of the strains, respectively. The post-cooking survival and growth capacity of the B. cereus strains appeared to be independent of their toxigenic profiles, whereas extracellular enzymatic activities were required for their vegetative growth. Due to the B. cereus spores’ abilities to survive cooking and return to their active cellular form, great care should be taken when handling ready-to-eat foods.

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Posted in Bacillus, Bacillus cereus, Bacterial Spores, 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, Spores

Research – Extending the Shelf Life of Raw Milk and Pasteurized Milk with Plantaricin FB-2

Posted on February 2, 2023 by | Leave a comment

MDPI

Abstract

Raw milk and pasteurized milk are characterized by a short shelf life, and drinking expired raw milk and pasteurized milk causes illness. In the study, Plantaricin FB-2 (extracted from Lactiplantibacillus plantarum FB-2) was added to liquid milk. By evaluating the microbial growth, acidity changes, protein content, and sensory changes in raw milk and pasteurized milk during storage, it was found that when Plantaricin FB-2 was added at 0.4 g/kg, the shelf life of raw milk was extended by 3 days (7 days if not added). The shelf life of pasteurized milk with Plantaricin FB-2 was extended to 31 days (25 days in the control group), and the optimal amount was 0.3 g/kg. This confirmed that Plantaricin FB-2 can effectively prolong the shelf life of raw and pasteurized milk. This study provides valuable information for the application of bacteriocins produced by Lactiplantibacillus plantarum in raw milk and pasteurized milk to improve their shelf life.

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Posted in bacteriocins, 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, Raw Milk

USDA Method Update – Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized Egg, Carcass, and Environmental Sponges

Posted on February 2, 2023 by | Leave a comment
This method describes the laboratory procedure for performing Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized Egg, Products and Carcass and Environmental Sponges

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Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiology, Microbiology Investigations, Salmonella

Research – Increased Multidrug-Resistant Salmonella enterica I Serotype 4,[5],12:i:- Infections Associated with Pork, United States, 2009–2018

Posted on February 2, 2023 by | Leave a comment

CDC

Abstract

Reports of Salmonella enterica I serotype 4,[5],12:i:- infections resistant to ampicillin, streptomycin, sulphamethoxazole, and tetracycline (ASSuT) have been increasing. We analyzed data from 5 national surveillance systems to describe the epidemiology, resistance traits, and genetics of infections with this Salmonella strain in the United States. We found ASSuT-resistant Salmonella 4,[5],12:i:- increased from 1.1% of Salmonella infections during 2009–2013 to 2.6% during 2014–2018; the proportion of Salmonella 4,[5],12:i:- isolates without this resistance pattern declined from 3.1% to 2.4% during the same timeframe. Among isolates sequenced during 2015–2018, a total of 69% were in the same phylogenetic clade. Within that clade, 77% of isolates had genetic determinants of ASSuT resistance, and 16% had genetic determinants of decreased susceptibility to ciprofloxacin, ceftriaxone, or azithromycin. Among outbreaks related to the multidrug-resistant clade, 63% were associated with pork consumption or contact with swine. Preventing Salmonella 4,[5],12:i:- carriage in swine would likely avert human infections with this strain.

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Posted in 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, Salmonella

USDA Methods Update – Detection, Isolation, and Identification of Top Seven Shiga Toxin-Producing Escherichia coli (STEC) from Meat Products, Carcass, and Environmental Sponges

Posted on February 2, 2023 by | Leave a comment

FSIS USDA

This method describes the laboratory procedure for analysis of raw and ready-to-eat meat products, and laboratory environmental sponge samples for the seven targeted STEC serogroups (O157, O26, O45, O103, O111, O121 and O145).

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Posted in E.coli O103, E.coli O111, E.coli O121, E.coli O145, E.coli O157, E.coli O157:H7, E.coli O26, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Microbiology, O103, O45

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

Hong Kong – Lap-mei (Chinese Preserved Meat) and Food Safety

Posted on February 2, 2023 by | Leave a comment

CFS

Lap-mei is a favourite food of many people, distinctive for its colour, aroma and taste.  There are three types of lap-mei available on the local market.  They are preserved Chinese sausages, preserved pork, and preserved ducks.  Recently, media reported that some people tried to prepare their own home-made lap-mei, which has raised food safety concerns.

Some of the curing ingredients used to prepare lap-mei (e.g. salt) have antimicrobial functions while sodium nitrate/nitrite can also inhibit the growth of Clostridium botulinum and its toxin production.  Improper conditions in processing of lap-mei may lead to food deterioration due to bacterial growth, and may affect health after consumption.  However, it is worth noting that Clostridium botulinum may grow in oxygen free and low acid food (such as home-made Chinese sausages) and produce lethal toxin without causing noticeable deterioration in the food.  Application of nitrate/ nitrite in curing should be limited to the amount required to achieve the intended effect only.  Nitrites may react with other substances found in meat forming nitrosamines, compounds that may cause human cancer.  Moreover, ingestion of significant amount of nitrite can cause methaemoglobinaemia, with red blood cells loses its ability to bind oxygen and causes hypoxia in the affected individuals.  The condition is characterised by headache, weakness and breathlessness, and a bluish discolouration of the skin and mucous membranes.  Infants and young children are more susceptible to this condition because their digestive and methaemoglobin reductase systems are still immature.

Members of the public should buy lap-mei from reliable retailers, maintain a balanced diet and avoid excessive consumption of lap-mei (especially for individuals with diabetes, heart disease and high cholesterol).  In addition, infants are highly susceptible to nitrite toxicity and should avoid consuming lap-mei.  The intake of lap-mei among young children should also be restricted.

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Posted in Clostridium, Clostridium botulinum, food contamination, food handler, Food Hazard, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Food Poisoning, Food Safety, Food Safety Alert, Food Safety Management, Food Safety Regulations, food safety training, Food Testing, Food Toxin

Research – Campylobacter jejuni and Campylobacter coli from Houseflies in Commercial Turkey Farms Are Frequently Resistant to Multiple Antimicrobials and Exhibit Pronounced Genotypic Diversity

Posted on February 1, 2023 by | Leave a comment

MDPI

Abstract

Campylobacter is a leading foodborne pathogen, and poultry are a major vehicle for infection. Houseflies play important roles in colonization of broiler flocks with Campylobacter but comparable information for turkey farms is limited. Here, we investigated houseflies as potential vectors for Campylobacter in 28 commercial turkey flocks. We characterized species, genotypes, and the antimicrobial resistance (AMR) profiles of Campylobacter from turkey feces and houseflies in the same turkey house. Of the 28 flocks, 25 yielded Campylobacter from turkey droppings and houseflies, with an average of 6.25 and 3.11 Campylobacter log CFU/g feces and log CFU/fly, respectively. Three flocks were negative for Campylobacter both in turkey feces and in houseflies. Both C. coli and C. jejuni were detected in turkey feces and houseflies, with C. coli more likely to be recovered from houseflies than feces. Determination of Campylobacter species, genotypes, and AMR profiles revealed up to six different strains in houseflies from a single house, including multidrug-resistant strains. For the predominant strain types, presence in houseflies was predictive of presence in feces, and vice versa. These findings suggest that houseflies may serve as vehicles for dissemination of Campylobacter, including multidrug-resistant strains, within a turkey house, and potentially between different turkey houses and farms in the same region.

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Posted in antimicrobial resistance, Campylobacter, campylobacter coli, Campylobacter jejuni, 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

India – Over 100 AP students fall ill, food poisoning suspected

Posted on February 1, 2023 by | Leave a comment

New Indian Express

GUNTUR: As many as 130 students fell sick  after consuming food at Gurukul school in Ramakrishnapuram in Palnadu district on Monday. Out of these students, 60 were admitted to hospital due to suspected food poisoning after they complained of vomiting and diarrhoea. As many as 650 students are studying at the Gurukul.

According to sources, a few students complained of stomach pain and nausea in the morning hours of Monday. The health officer at the school gave them the required medicines. However, the situation turned worse when several other students too took ill with similar symptoms. Later, they shifted the students to the Sattenapalli area hospital.

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Posted in Food Illness, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Poisoning, Foodborne Illness, Illness, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Poisoning