Author Archives: KSW

Research – Long chain unsaturated fatty acids alter growth and reduce biofilm formation of Cronobacter sakazakii

Posted on May 10, 2024 | Leave a comment

Wiley Online

Cronobacter sakazakii is a foodborne pathogen predominately transmitted through contaminated dried foods and affects populations including neonates, infants, and the elderly. Following several recent outbreaks, it is now a notifiable infection in those under 12 months of age. Current control methods include strict manufacturing guidelines, with monitoring of this genus a legal requirement in powdered infant formula production. Fatty acids have long been known as antimicrobials, with long-chain fatty acids increasingly identified as agents that target virulence factors. This study gives insight into the changes promoted by three long-chain unsaturated fatty acids (oleic, linoleic, and α-linolenic) on C. sakazakii growth, morphology, and biofilm formation. Each fatty acid was individually introduced to C. sakazakii 29544 both as a sole carbon source and as an addition to complex media. Following comparison to the untreated control, bacterial cells treated with these fatty acids showed a significant and media-dependent impact on growth and biofilm inhibition. With further characterization, long-chain fatty acids, including α-linolenic acid, could be utilized as a control method with minimal safety constraints regarding their use in the food production environment.

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Posted in Cronobacter sakazakii, cross contamination, Decontamination Microbial, Food Microbiology Research, Food Pathogen, Food Technology, Pathogen, pathogenic, Research, Technology

Research – Fermented Rapeseed and Soybean Alone and in Combination with Macro Algae Inhibit Human and Pig Pathogenic Bacteria In Vitro

Posted on May 10, 2024 | Leave a comment

MDPI

Abstract

Higher plants produce secondary metabolites expressing antimicrobial effects as a defense mechanism against opportunistic microorganisms living in close proximity with the plant. Fermentation leads to bioconversion of plant substrates to these bioactive compounds and their subsequent release via breakdown of plant cell walls. Fermented feed products have recently started to become implemented in the pig industry to reduce overall disease pressure and have been found to reduce events such as post-weaning diarrhea. In this study, we investigate the antimicrobial potential of fermented soybean- and rapeseed-based pig feed supplements with and without added seaweed. The antimicrobial effect was tested in a plate well diffusion assay against a range of known human and livestock pathogenic bacteria. Further, we investigate the metabolite profiles based on liquid-chromatography mass-spectrometry (LC-MS) analysis of the fermented products in comparison to their unfermented constituents. We observed a pronounced release of potential antimicrobial secondary metabolites such as benzoic acids when the plant material was fermented, and a significantly increased antimicrobial effect compared to the unfermented controls against several pathogenic bacteria, especially Salmonella enterica Typhimurium, Listeria monocytogenes, Yersinia enterocolitica, and a strain of atopic dermatitis causing Staphylococcus aureus CC1. In conclusion, fermentation significantly enhances the antimicrobial properties of rapeseed, soybean, and seaweed, offering a promising alternative to zinc oxide for controlling pathogens in piglet feed. This effect is attributed to the release of bioactive metabolites effective against pig production-relevant bacteria.

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

Research – Analysis of flour and rice shows high levels of harmful fungal toxins

Posted on May 9, 2024 | 1 comment

Medical Express

By analyzing samples of flour and rice stored in homes in Ribeirão Preto, in the interior of the state of São Paulo (Brazil), researchers from the University of São Paulo (USP) found the presence of high levels of fungal toxins (mycotoxins). The study is published in the journal Food Research International.

The six toxins of concern were found in all the food samples analyzed: aflatoxins (AFs), fumonisins (FBs), zearalenone (ZEN), T-2 toxin, deoxynivalenol (DON), and ochratoxin A (OTA). In the case of the mycotoxins FBs, ZEN, and DON, the levels were above the tolerance limit set by the health authorities. This study was the first in Brazil to use biomarkers to characterize the risk associated with mycotoxins in the diet of children and adolescents.

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Posted in Aflatoxin, Aflatoxin B1, deoxynivalenol, DON, Food Microbiology Research, Fumomisins, Fumonsins, fungi, Fusarium Toxin, mold, Mold Toxin, Mycotoxin, Ochratoxin, Ochratoxin A, Research, Zearalenone

Research – Officials find contaminated food played role in Guillain-Barré outbreak

Posted on May 9, 2024 | Leave a comment

Food Safety News

Consumption of poorly prepared food has been identified as a factor in a fatal Guillain-Barré outbreak in Guatemala.

Findings come from the results of case control studies announced by the Ministry of Public Health and Social Assistance (MSPAS) and the Guatemalan Institute of Social Security (IGSS).

Guillain-Barré syndrome (GBS) is a rare disorder where the body’s immune system damages nerves. The cause is not fully understood but the syndrome often follows infection with a virus or bacteria. Infection with Campylobacter jejuni, which causes gastroenteritis, including symptoms of nausea, vomiting and diarrhea, is one of the most common risk factors for GBS.

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Posted in Campylobacter, Campylobacter jejuni, gastroenteritis, Gastrointestinal Infection, Guillain-Barré

Research-Raw meat-based diet for pets: a neglected source of human exposure to Salmonella and pathogenic Escherichia coli clones carrying mcr, Portugal, September 2019 to January 2020

Posted on May 8, 2024 | Leave a comment

Eurosurveillance

The pet industry has evolved in recent decades due to increasing pet populations, stronger human–pet bonds and demand for high-quality pet food products [1,2]. Processed pet food manufactured with various processing methods (e.g. grinding, cooking, extrusion and dehydration) has traditionally been considered microbiological safe and nutritionally suitable for feeding pets [1,3]. However, since some pet owners consider unprocessed food healthier, raw meat-based diets (RMBDs) for dogs have gained popularity [1,2,4]. The RMBDs are mainly composed of uncooked or minimally processed meat, bones and organs, with freezing as the primary treatment, and are considered to be more natural than conventional processed pet food [1,5]. Nevertheless, the scientific evidence supporting RMBD benefits is scarce, and many veterinary professional organisations (e.g. the World Small Animal Veterinary Association) and international public health agencies (e.g. the United States (US) Centers for Disease Control and Prevention (CDC)) view them as potential health hazards for both animals and humans [1,5]; awareness of this issue appears less evident in Europe [6]. The safety concerns associated with RMBDs are related to the potential contamination of raw ingredients with zoonotic pathogenic bacteria and parasites [1,3,4]. Such contamination could lead to the spread of these pathogens to both pets and humans cohabitating with pets, through direct contact with the pet or its feed, or indirectly through contact with contaminated household surfaces or hands during feed preparation.

In the European Union (EU), legal requirements for the use of animal by-products and derived products not intended for human consumption are established, including those to produce processed or raw pet food, helping to ensure microbiological safety [7]. Nevertheless, since 2020, there have been more than 20 notifications or recalls of pet food and RMBD in the EU due to the detection of zoonotic pathogens, particularly  and pathogenic  [8], and also cases of human infections with  and Shiga toxin-producing  (STEC) linked to exposure to RMBDs [9–11]. Several studies have also established a correlation between the microbiota of pets and their owners, including the presence of antibiotic-resistant strains, with pet food as a potential source [12,13]. However, certain antibiotic-resistant bacteria and genes of public health concern, such as the  gene conferring resistance to the last-line antibiotic colistin, have not been extensively studied in pet food and RMBDs [1,14–16]. Consequently, these antibiotic-resistant strains and genes have not been recognised as notable food safety issues in the context of the pet food industry [6]. To address this knowledge gap, we aimed to investigate the occurrence of and further characterise  and other  resistant to critical antibiotics, such as colistin, in dog food, including RMBDs, that is available in stores in Portugal to investigate if they represent a possible source of these hazards to public health.

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Posted in E.coli, Pet Food, Pet Food Aflatoxin, Pet Food Enterobacteriaceae, Pet Food Illness, Pet Food Listeria monocytogenes, Pet Food Recall, Pet Food Salmonella, Pet Food Testing, raw pet food, Research, STEC, STEC E.coli

Research – Microbiological Risks of Traditional Raw Cow’s Milk Cheese (Koryciński Cheeses)

Posted on May 8, 2024 | Leave a comment

MDPI

Abstract

Traditional and regional foods have been increasing in popularity among consumers in Poland for many years. The observed trend of searching for natural and authentic taste encourages many producers to craft products from raw milk, including Koryciński cheeses. The aim of this study was to assess the microbiological hazards resulting from the presence of pathogenic bacteria in Koryciński cheeses available in retail trade. The tests were carried out using accredited methods, including the detection of the presence of Salmonella spp., the enumeration of Listeria monocytogenes, the enumeration of coagulase-positive staphylococci, and the detection of staphylococcal enterotoxins in food when the number of coagulase-positive staphylococci in the sample exceeded the limit of 105 cfu/g. The research material consisted of 45 Koryciński cheeses. The tests conducted revealed that Salmonella spp. was not detected in any of the examined cheeses. However, coagulase-positive staphylococci were present in 68.9% of the samples. In as many as 15 tested cheeses, the level of S. aureus contamination was above 105 cfu/g; therefore, these samples were tested for the presence of staphylococcal enterotoxins. The presence of staphylococcal enterotoxins was found in one Koryciński cheese. In four cheeses, the number of L. monocytogenes exceeded the level of 102 cfu/g, the limit specified in Regulation 2073/2005 on microbiological criteria for foodstuffs. The obtained research results confirm the validity of monitoring the microbiological quality of Koryciński cheeses and the need to increase awareness of ensuring proper hygienic conditions of production, including the increased risk associated with unpasteurized milk products.

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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

Research – Modelling Growth Kinetics of Escherichia coli and Background Microflora in Hydroponically Grown Lettuce

Posted on May 7, 2024 | Leave a comment

MDPI

Abstract

Hydroponic cultivation of lettuce is an increasingly popular sustainable agricultural technique. However, Escherichia coli, a prevalent bacterium, poses significant concerns for the quality and safety of hydroponically grown lettuce. This study aimed to develop a growth model for E. coli and background microflora in hydroponically grown lettuce. The experiment involved inoculating hydroponically grown lettuce with E. coli and incubated at 4, 10, 15, 25, 30, 36 °C. Growth models for E. coli and background microflora were then developed using Origin 2022 (9.9) and IPMP 2013 software and validated at 5 °C and 20 °C by calculating root mean square errors (RMSEs). The result showed that E. coli was unable to grow at 4 °C and the SGompertz model was determined as the most appropriate primary model. From this primary model, the Ratkowsky square root model and polynomial model were derived as secondary models for E. coli-R168 and background microflora, respectively. These secondary models determined that the minimum temperature (Tmin) required for the growth of E. coli and background microflora in hydroponically grown lettuce was 6.1 °C and 8.7 °C, respectively. Moreover, the RMSE values ranged from 0.11 to 0.24 CFU/g, indicating that the models and their associated kinetic parameters accurately represented the proliferation of E. coli and background microflora in hydroponically grown lettuce.

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Posted in E.coli, Food Microbiology Research, Food Technology, Research, Technology

ECDC – Facts on Ciguatera fish poisoning

Posted on May 6, 2024 | Leave a comment

ECDC

Ciguatera poisoning (CP) is caused by consumption of fish that have accumulated ciguatoxins in their flesh. CP is endemic in tropical and subtropical regions, particularly in the Pacific and Indian Oceans and the Caribbean Sea. Isolated outbreaks have occurred sporadically in Europe but with an increasing frequency in temperate areas like the Canary Islands, Spain.

CP is not under routine surveillance in the European Union (EU), but unexpected, potentially serious cross-border biological threats to health are monitored by ECDC [1]. Cases are usually not notified in national surveillance systems but may be reported to national poisoning centres.

Ciguatoxins

Ciguatoxins (CTXs) are temperature-stable, so they are not destroyed by cooking or by freezing the fish. Furthermore, the toxins are colourless, odourless, and flavourless, which make it impossible to taste or smell them [2,3].

Transmission

CP is caused by the consumption of herbivorous fish that feed on toxic microalgae (Gambierdiscus spp. and Fukuyoa spp.), which are attached to macrophytes or dead corals, and from carnivorous fish that have consumed toxic herbivorous fish [3,4].

Over 400 known fish species from tropical and subtropical waters have been classified as potential carriers of CTXs. Examples of the fish most frequently associated with cases of CP include barracuda, grouper, amberjack, snapper, moray eel, hogfish, mackerel, surgeonfish, and parrotfish. Greater severity of illness is associated with eating fish head or organs. It is therefore advisable to avoid consuming visceral organs, roe (fish eggs), and carcasses (e.g. heads, eyes, and bones) of these fish species [4-6].

Person-to-person transmission of CTXs is extremely rare, but transmission of toxin from mother to child during breastfeeding or across the placenta, as well as during sexual intercourse, has been described [6-10].

Clinical features and sequelae

Intoxication of humans occurs via consumption of fish containing CTXs. In humans, CTXs activate voltage-gated sodium channels in cell membranes, increasing sodium ion permeability and depolarizing the nerve cell. Clinical presentation varies according to the individual characteristics and the geographical origin of the CTXs. Gastrointestinal symptoms can precede or accompany neurological symptoms, which usually appear two to 48 hours after eating the contaminated fish. Symptoms can include nausea, vomiting, diarrhoea, abdominal cramps, paraesthesia of lips, tongue and extremities, cold allodynia (burning pain caused by a normally innocuous cold stimulus), a metallic taste in the mouth, arthralgia, myalgia, pruritus without urticaria or erythema, muscle weakness, blurred vision, painful intercourse, hypotension, and bradycardia [4,8,11].

Cold allodynia is characteristic of CP, although it is not present in all patients. Neurological symptoms usually resolve within weeks, although some symptoms can last for months. Recurrent symptoms can occur following the ingestion of certain food or beverages such as alcohol, nuts, or non-toxic fish. CP is rarely fatal, but death can occur in severe cases due to severe dehydration, cardiovascular shock, or respiratory failure [4,8,11].

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Posted in Algal Blooms, Algal Toxin, Ciguatera, Ciguatera Poisoning, Food Microbiology Research, Research

Research – FDA Publishes Landmark Final Rule to Enhance the Safety of Agricultural Water

Posted on May 6, 2024 | Leave a comment

FDA

Today, the U.S. Food and Drug Administration (FDA) published a final rule on agricultural water that represents an important step toward enhancing the safety of produce. The revised requirements are intended to enhance public health by improving the safety of water used in produce cultivation. The revisions are also designed to be practical across various agricultural water systems, uses, and practices, while remaining adaptable to future advancements in agricultural water quality science.

The final rule replaces certain pre-harvest agricultural water requirements for covered produce (other than sprouts) in the 2015 produce safety rule with requirements for systems-based agricultural water assessments to determine and guide appropriate measures to minimize potential risks associated with pre-harvest agricultural water. Specifically, this rule:

  • Establishes requirements for agricultural water assessments that evaluate a variety of factors that are key determinants of contamination risks associated with pre-harvest agricultural water. This includes an evaluation of the water system, water use practices, crop characteristics, environmental conditions, potential impacts on water from adjacent and nearby land, and other relevant factors.
  • Includes testing pre-harvest agricultural water as part of an assessment in certain circumstances.
  • Requires farms to implement effective mitigation measures within specific timeframes based on findings from their assessments. Hazards related to certain activities associated with adjacent and nearby land uses are subject to expedited mitigation.
  • Adds new options for mitigation measures, providing farms with additional flexibility in responding to findings from their pre-harvest agricultural water assessments.

Farms are required to conduct assessments of their pre-harvest agricultural water annually, and whenever a significant change occurs, to identify any conditions likely to introduce known or reasonably foreseeable hazards into or onto covered produce or food contact surfaces.

These revised requirements reflect recent science, findings from investigations of several produce-related outbreaks, and feedback from a variety of stakeholders on the agricultural water requirements in the Produce Safety Rule, which were previously published in 2015. These revisions will more comprehensively address a known route of microbial contamination that can lead to preventable foodborne illness.

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Posted in Bore Hole Water, Contaminated water, FDA, Food Microbiology Research, Research, Water, water microbiology, Water Safety

Research – Antibiotic Resistant Escherichia coli in Uncooked Meat Purchased from Large Chain Grocery Stores and in Raw Dog Food Purchased From Pet Stores in the Same City

Posted on May 6, 2024 | Leave a comment

BIORXIV

Abstract

Although previous studies have associated feeding dogs uncooked meat with their carriage and excretion of antibiotic resistant (ABR) Escherichia coli, this practice remains popular amongst dog owners in some countries, including the UK. Uncooked meat fed to dogs is purchased from stores selling meat primarily for human consumption, or it is a brand of commercial raw dog food (RDF), which is commonly sold frozen and thawed prior to feeding. We tested 58 packets of uncooked meat (beef, chicken, lamb and pork) purchased from large chain grocery stores (15 stores) and 15 packets of thawed, chicken-based RDF (11 brands) for the presence of ABR E. coli. All samples were purchased from the city of Bristol, UK. Among grocery store-purchased meat, chicken samples were significantly more likely to be positive for E. coli resistant to amoxicillin, spectinomycin, streptomycin, and the critically important antibiotics cefotaxime and ciprofloxacin, than other types of meat. When comparing grocery store chicken to chicken-based RDF we found no significant difference in sample-level positivity for resistant E. coli, which, for RDF was 80% (amoxicillin), 80% (spectinomycin), 87% (streptomycin), 27% (amoxicillin-clavulanate), 27% (cefotaxime) and 47% (ciprofloxacin). We conclude that despite it having been purchased frozen and thawed prior to testing according to the manufacturer’s instructions, contamination of RDF with ABR E. coli is similar to that of uncooked meat primarily intended for human consumption after cooking, and so the same strict hygiene practices are advised when handling RDF as uncooked meat. Our findings provide a rationale to explain why feeding uncooked meat or RDF to dogs in the city of Bristol is associated with them excreting E. coli resistant to critically important antibiotics.

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Posted in Animal Feed Recall, Animal Feed Salmonella, Animal Feed Testing, Antibiotic Resistance, E.coli, Pet Food, Pet Food Illness, Pet Food Recall, Pet Food Salmonella, Pet Food Testing, raw pet food