Category Archives: Microbial growth

Research – Bacterial pathogens and climate change

Posted on December 31, 2022 by | Leave a comment

The Lancet

Read the full article at the link above

A systematic analysis of the literature showed that 58% of infectious diseases in humans have been aggravated at some point by climatic hazards, such as changes in temperatures and water and food availability.

The leading pathogens responsible (eg, S aureus, E coli, K pneumoniae, S pneumoniae, and non-typhoidal Salmonella) have all been found to have climate-dependent reactions, causing an increase in their diffusion and even resistance to treatment.

 For example, sharp temperature decreases have been associated with an increased incidence of pneumonia, and increased morbidity in cold and humid weather.

 

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Posted in Food Microbiology Blog, Food Pathogen, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Pathogen, pathogenic

Research -Control measures for Shiga toxin-producing Escherichia coli (‎STEC)‎ associated with meat and dairy products: meeting report

Posted on December 31, 2022 by | Leave a comment

WHO

Although Shiga toxin-producing Escherichia coli (STEC) have been isolated from a variety of food production animals, they are most commonly associated with ruminants from which we derive meat and milk. Because of the widespread and diverse nature of ruminant-derived food production, coupled with the near ubiquity of STEC worldwide, there is no single definitive solution for controlling STEC that will work alone or in all situations. Instead, the introduction of multiple interventions applied in sequence, as a “multiple-hurdle scheme” at several points throughout the food chain (including processing, transport and handling) will be most effective.

This report summarizes the review and evaluation of interventions applied for the control of STEC in cattle, raw beef and raw milk and raw milk cheese manufactured from cows’ milk, and also evaluates available evidence for other small ruminants, swine and other animals. The information is presented from primary production, to the end of processing, providing the reader with information on the currently available interventions based on the latest scientific evidence.

This work was undertaken to support the development of guidelines for the control of STEC in beef, raw milk and cheese produced from raw milk by the Codex Committee on Food Hygiene (CCFH).

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Posted in Decontamination Microbial, E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, STEC, STEC E.coli

Research – Listeria monocytogenes—How This Pathogen Uses Its Virulence Mechanisms to Infect the Hosts

Posted on December 31, 2022 by | Leave a comment

MDPI

Abstract

Listeriosis is a serious food-borne illness, especially in susceptible populations, including children, pregnant women, and elderlies. The disease can occur in two forms: non-invasive febrile gastroenteritis and severe invasive listeriosis with septicemia, meningoencephalitis, perinatal infections, and abortion. Expression of each symptom depends on various bacterial virulence factors, immunological status of the infected person, and the number of ingested bacteria. Internalins, mainly InlA and InlB, invasins (invasin A, LAP), and other surface adhesion proteins (InlP1, InlP4) are responsible for epithelial cell binding, whereas internalin C (InlC) and actin assembly-inducing protein (ActA) are involved in cell-to-cell bacterial spread. L. monocytogenes is able to disseminate through the blood and invade diverse host organs. In persons with impaired immunity, the elderly, and pregnant women, the pathogen can also cross the blood–brain and placental barriers, which results in the invasion of the central nervous system and fetus infection, respectively. The aim of this comprehensive review is to summarize the current knowledge on the epidemiology of listeriosis and L. monocytogenes virulence mechanisms that are involved in host infection, with a special focus on their molecular and cellular aspects. We believe that all this information is crucial for a better understanding of the pathogenesis of L. monocytogenes infection.

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

Research – Variability in Cold Tolerance of Food and Clinical Listeria monocytogenes Isolates

Posted on December 30, 2022 by | Leave a comment

MDPI

Abstract

The aim of this study was to investigate the level of strain variability amongst food and clinical Listeria monocytogenes isolates growing at low temperatures (4 and 7 °C) in both laboratory media and real food matrices. Isolates (n = 150) grown in laboratory media demonstrated a large variation in growth profiles measured using optical density.
Overall, it was noted that clinical isolates exhibited a significantly higher growth rate (p ≤ 0.05) at 7 °C than the other isolates. Analysis of variance (ANOVA) tests of isolates grouped using Multi Locus Sequence Typing (MLST) revealed that clonal complex 18 (CC18) isolates were significantly (p ≤ 0.05) faster growing at 4 °C than other CC-type isolates while CC101, CC18, CC8, CC37 and CC14 were faster growing than other CC types at 7 °C. Euclidean distance and Ward method-based hierarchical clustering of mean growth rates classified 33.33% of isolates as faster growing.
Fast and slow growing representative isolates were selected from the cluster analysis and growth rates were determined using plate count data in laboratory media and model food matrices. In agreement with the optical density experiments, CC18 isolates were faster and CC121 isolates were slower than other CC types in laboratory media, UHT milk and fish pie. The same trend was observed in chocolate milk but the differences were not statistically significant. Moreover, pan-genome analysis (Scoary) of isolate genome sequences only identified six genes of unknown function associated with increased cold tolerance while failing to identify any known cold tolerance genes. Overall, an association that was consistent in laboratory media and real food matrices was demonstrated between isolate CC type and increased cold tolerance.

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Posted in 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

RASFF Alerts – Animal Feed – Salmonella – Fish Meal – Turkey Processed Protein – Rapeseed Meal

Posted on December 30, 2022 by | Leave a comment

RASFF

Salmonella in fish meal from Poland in Lithuania

RASFF

Salmonella Muenster and Salmonella Rissen in turkey processed animal protein from Spain in Belgium

RASFF

Salmonella spp. in rapeseed meal from Germany in Finland, Denmark and Sweden

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Posted in Animal by Products, Animal Feed, Animal Feed Salmonella, Animal Feed Testing, Antimicrobials, 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, RASFF, Salmonella

Research – Inhibition of Aflatoxin Production by Citrinin and Non-Enzymatic Formation of a Novel Citrinin-Kojic Acid Adduct

Posted on December 29, 2022 by | Leave a comment

MDPI

Abstract

Screening for microorganisms that inhibit aflatoxin production from environments showed that Penicillium citrinum inhibited aflatoxin production by Aspergillus parasiticus. The inhibitory substance in the culture medium of P. citrinum was confirmed to be citrinin (CTN). RT-PCR analyses showed that CTN did not inhibit expressions of aflatoxin biosynthetic genes (aflR, pksL1, and fas-1) of A. parasiticus, whereas feeding experiments using A. parasiticus showed that CTN inhibited the in vivo conversion of dihydrosterigmatocystin to AFB2·AFG2. These results suggest that CTN inhibits a certain post-transcriptional step in aflatoxin biosynthesis. CTN in the culture medium of A. parasiticus was found to be decreased or lost with time, suggesting that a certain metabolite produced by A. parasiticus is the cause of the CTN decrease; we then purified, characterized, and then analyzed the substance. Physico-chemical analyses confirmed that the metabolite causing a decrease in CTN fluorescence was kojic acid (KA) and the resulting product was identified as a novel substance: (1R,3S,4R)-3,4-dihydro-6,8-dihydroxy-1-(3-hydroxy-6-(hydroxymethyl)-4-oxo-4H-pyran-2-yl)-3,4,5-trimethyl-1H-isochromene-7-carboxylic acid, which was named “CTN-KA adduct”. Our examination of the metabolites’ toxicities revealed that unlike CTN, the CTN-KA adduct did not inhibit aflatoxin production by A. parasiticus. These results indicate that CTN’s toxicity was alleviated with KA by converting CTN to the CTN-KA adduct.

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Posted in Aflatoxin, Aflatoxin B1, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Penicillium spp

Composition-Based Risk Estimation of Mycotoxins in Dry Dog Foods

Posted on December 29, 2022 by | Leave a comment

MDPI

Abstract

The risk of mycotoxins co-occurrence in extrusion-produced dry foods increases due to their composition based on various grains and vegetables. This study aimed to validate a risk estimation for the association between ingredients and the ELISA-detected levels of DON, FUM, ZEA, AFs, T2, and OTA in 34 dry dog food products. The main ingredients were corn, beet, and oil of different origins (of equal frequency, 79.41%), rice (67.6%), and wheat (50%). DON and FUM had the strongest positive correlation (0.635, p = 0.001). The presence of corn in the sample composition increased the median DON and ZEA levels, respectively, by 99.45 μg/kg and 65.64 μg/kg, p = 0.011. In addition to DON and ZEA levels, integral corn presence increased the FUM median levels by 886.61 μg/kg, p = 0.005. For corn gluten flour-containing samples, DON, FUM, and ZEA median differences still existed, and OTA levels also differed by 1.99 μg/kg, p < 0.001. Corn gluten flour presence was strongly associated with DON levels >403.06 μg/kg (OR = 38.4, RR = 9.90, p = 0.002), FUM levels >1097.56 μg/kg (OR = 5.56, RR = 1.45, p = 0.048), ZEA levels >136.88 μg/kg (OR = 23.00, RR = 3.09, p = 0.002), and OTA levels >3.93 μg/kg (OR = 24.00, RR = 3.09, p = 0.002). Our results suggest that some ingredients or combinations should be avoided due to their risk of increasing mycotoxin levels.

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Posted in Aflatoxin, Animal Feed, Animal Feed Mould Toxin, Animal Feed Testing, Aspergillus Toxin, Decontamination Microbial, deoxynivalenol, DON, Food Micro Blog, Food Microbiology Blog, Food Toxin, Fumomisins, Fumonsins, Fusarium Toxin, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Mold Toxin, Mould Toxin, Mycotoxin, Ochratoxin A, OTA, Pet Food, Pet Food Aflatoxin, Pet Food Testing, Zearalenone

USA – FDA Warning Letter – Bainbridge Beverage West, LLC- Microbial Risk

Posted on December 29, 2022 by | Leave a comment

FDA

The U.S Food and Drug Administration (FDA) inspected your juice manufacturing facility, located at 2335 Del Monte Street, West Sacramento, CA 95691 on June 9, 10, 22, 24, and 29, 2022. We found that you have serious violations of the FDA’s juice Hazard Analysis and Critical Control Point (HACCP) regulation, Title 21, Code of Federal Regulations, Part 120 (21 CFR Part 120). In accordance with 21 CFR 120.9, failure of a processor to have and implement a HACCP plan that complies with the requirements of 21 CFR Part 120 renders the juice products adulterated within the meaning of Section 402(a)(4) of the Federal Food, Drug and Cosmetic Act (the Act) [21 U.S.C. § 342(a)(4)]. Accordingly, your juice products are adulterated in that they have been prepared, packed, or held under insanitary conditions whereby they may have been contaminated with filth, or whereby they may have been rendered injurious to health. You may find the Act, FDA’s juice HACCP regulations and the Juice HACCP Hazards and Controls Guidance through links in FDA’s home page at www.fda.gov.External Link Disclaimer

To date, the agency has not received a written response from your firm regarding the violations noted on the Form FDA-483, Inspectional Observations, which was issued to your firm at the conclusion of the inspection.

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Posted in Decontamination Microbial, FDA, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, HACCP, Hepatitis A, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk

USA – FDA Warning Letter Big Olaf Creamery LLC dba Big Olaf – Listeria monocytogenes

Posted on December 29, 2022 by | Leave a comment

FDA

The United States Food and Drug Administration (FDA) inspected your ready-to-eat (RTE) ice cream manufacturing facility, located at 2001 Cattlemen Rd Unit 123, Sarasota, Florida, from July 19 to September 01, 2022. The inspection was initiated as part of a joint investigation with the Florida Department of Health (FL DOH) and Florida Department of Agriculture & Consumer Services (FDACS) of a multistate outbreak of Listeria monocytogenes (L. monocytogenes) infections linked to ice cream supplied by your facility. According to the Centers for Disease Control and Prevention (CDC), 28 ill people from 11 states were infected with the outbreak strain of L. monocytogenes. On July 13, 2022, your firm recalled all ice cream products, lots, and expiration dates of Big Olaf brand ice cream through June 30, 2022, because they had the potential of being contaminated with L. monocytogenes. CDC and FDA have determined, based upon the epidemiological data and Whole Genome Sequencing (WGS) matches between clinical and FDACS environmental and finished product samples that ice cream manufactured at this facility was the source of this multistate L. monocytogenes outbreak.

During the inspection of your facility, FDA found serious violations of the Current Good Manufacturing Practice, Hazard Analysis, and Risk-Based Preventative Controls for Human Food regulation (CGMP & PC rule), Title 21, Code of Federal Regulations, Part 117 (21 CFR Part 117).

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Posted in food bourne outbreak, Food Illness, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Foodborne Illness, foodborne outbreak, foodbourne outbreak, Illness, Listeria, Listeria monocytogenes, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, outbreak

Research – Concept about the Virulence Factor of Legionella

Posted on December 29, 2022 by | Leave a comment

MDPI

Abstract

Pathogenic species of Legionella can infect human alveolar macrophages through Legionella-containing aerosols to cause a disease called Legionellosis, which has two forms: a flu-like Pontiac fever and severe pneumonia named Legionnaires’ disease (LD). Legionella is an opportunistic pathogen that frequently presents in aquatic environments as a biofilm or protozoa parasite. Long-term interaction and extensive co-evolution with various genera of amoebae render Legionellae pathogenic to infect humans and also generate virulence differentiation and heterogeneity. Conventionally, the proteins involved in initiating replication processes and human macrophage infections have been regarded as virulence factors and linked to pathogenicity. However, because some of the virulence factors are associated with the infection of protozoa and macrophages, it would be more accurate to classify them as survival factors rather than virulence factors. Given that the molecular basis of virulence variations among non-pathogenic, pathogenic, and highly pathogenic Legionella has not yet been elaborated from the perspective of virulence factors, a comprehensive explanation of how Legionella infects its natural hosts, protozoans, and accidental hosts, humans is essential to show a novel concept regarding the virulence factor of Legionella. In this review, we overviewed the pathogenic development of Legionella from protozoa, the function of conventional virulence factors in the infections of protozoa and macrophages, the host’s innate immune system, and factors involved in regulating the host immune response, before discussing a probably new definition for the virulence factors of Legionella.

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Posted in Decontamination Microbial, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Legionella, Legionnaires’ disease, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk