Category Archives: pathogenic

Research – Exploring Propolis as a Sustainable Bio-Preservative Agent to Control Foodborne Pathogens in Vacuum-Packed Cooked Ham

Posted on May 4, 2024 by | Leave a comment

MDPI

Abstract

The search for natural food additives makes propolis an exciting alternative due to its known antimicrobial activity. This work aims to investigate propolis’ behaviour as a nitrite substitute ingredient in cooked ham (a ready-to-eat product) when confronted with pathogenic microorganisms of food interest. The microbial evolution of Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, and Clostridium sporogenes inoculated at known doses was examined in different batches of cooked ham. The design of a challenge test according to their shelf life (45 days), pH values, and water activity allowed the determination of the mesophilic aerobic flora, psychotropic, and acid lactic bacteria viability. The test was completed with an organoleptic analysis of the samples, considering possible alterations in colour and texture. The cooked ham formulation containing propolis instead of nitrites limited the potential growth (δ < 0.5 log10) of all the inoculated microorganisms until day 45, except for L. monocytogenes, which in turn exhibited a bacteriostatic effect between day 7 and 30 of the storage time. The sensory analysis revealed the consumer’s acceptance of cooked ham batches including propolis as a natural additive. These findings suggest the functionality of propolis as a promising alternative to artificial preservatives for ensuring food safety and reducing the proliferation risk of foodborne pathogens in ready-to-eat products.

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Posted in Bacillus, Bacillus cereus, Bio-Preservative, Clostridium, Clostridium botulinum, Clostridium sporogenes, Food Microbiology Research, Food Pathogen, Pathogen, pathogenic, Propolis, psychrotrophic bacteria, Research, Staphylococcus aureus

Taiwan – Taipai – Causes clarified in food poisoning case

Posted on May 1, 2024 by | Leave a comment

Taipei Times

A suspected food poisoning incident at a Hi-Lai Harbour restaurant at Kaohsiung Arena was not caused by norovirus or rotavirus, but might have been caused by pathogenic bacteria, the Centers for Disease Control (CDC) said yesterday.

Testing for viral pathogens was negative for the two common causes of diarrhea, CDC Deputy Director-General Tseng Shu-hui (曾淑慧) said.

As of 9am on Monday, the number of people who had sought medical attention after dining at the upscale buffet restaurant in Zuoying District (左營) on Friday and Saturday last week had increased to 52 since Saturday, when 11 diners were first reported to have fallen ill, the Kaohsiung Health Department said in a statement.

All of the 52 people reported diarrhea and abdominal pain, while a handful also reported nausea and vomiting, the department said.

It had previously collected specimens from seven people who fell ill after eating at the branch and from 48 employees who handle food at the restaurant, as well as food samples.

Testing on the customers and employees came back negative for viral pathogens, meaning it is likely that pathogenic bacteria were involved, Tseng said.

Common bacteria that cause foodborne illness include Vibrio parahaemolyticus, salmonella, enteropathogenic Escherichia coli, Staphylococcus aureus, Vibrio cholerae and Clostridium botulinum, she said, adding that testing was being conducted to clarify the situation.

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Posted in food bourne outbreak, Food Illness, Food Pathogen, Foodborne Illness, foodborne outbreak, foodbourne outbreak, Illness, outbreak, Pathogen, pathogenic

Research – Assessment of the chemical profile and potential biocontrol of Amphora coffeaeformis against foodborne pathogens and Culex pipiens L. to ensure food safety

Posted on April 21, 2024 by | Leave a comment

Wiley Online

Abstract

The extensive use of synthetic antibiotics and insecticides in controlling microbes and insect spreads led to a build-up of resistance strains and caused negative impacts on human health through bioaccumulation in food and the environment. The present study assessed the antimicrobial activity of Amphora coffeaeformis (A. coffeaeformis) ethanolic extract against foodborne pathogenic microbes as well as assessed its ability to control Culex pipiens L. (C. pipiens) larvae. The gas chromatography–mass spectrum (GC/MS) and high-performance liquid chromatography (HPLC) analysis showed that A. coffeaeformis extract was rich with phenolic compounds, organosulfur compounds, carboxylic acids, amino acids, organic quinoline, dipeptide and monosaccharide. The extract of A. coffeaeformis showed antibacterial capability against all tested bacteria, with minimal inhibition concentration (MIC) values ranging from 20.2 to 66.7 g/mL, as well as antifungal effects against all tested mycotoxigenic fungi, with MIC values ranging from 113.62, 68.95 and 49.37 μg/mL mg/mL. Furthermore, the extract showed high larvicidal activity against C. pipiens larvae at 24, 48, and 72 h, respectively. LC50 values decreased gradually with the treatment period. Likewise, the adult emergence and growth index were significantly negatively related to increasing extract concentrations. Moreover, the extract exhibited a noteworthy depletion in the reproductive potential and increased sterility index of C. pipiens females developed of treated larvae. Besides a reduction in egg hatching percent, increase pupal malformations, increase and adult abnormalities. C. pipiens biochemical markers; glutathione-S-transferase, carboxylesterase, acetylcholinesterase, α-esterase and cytochrome P-450 showed significant alteration after the extract exposure. Overall, these findings promise the application possibility of A. coffeaeformis extract as a biopreservator against foodborne pathogens and as bioinsecticides for mosquito control as well.

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

Researchers Estimate Leafy Greens Foodborne Illness Outbreaks Cost U.S. $5 Billion Annually

Posted on April 18, 2024 by | Leave a comment

Food Safety.com

A recent review authored by researchers from Ohio State University has established pathogen-specific foodborne illness burden estimates for leafy greens in the U.S. by combining three outbreak-based attribution models with illness incidence and economic cost models.

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Posted in food bourne outbreak, Food Illness, Food Microbiology Research, Food Pathogen, Foodborne Illness, foodborne outbreak, foodbourne outbreak, Illness, outbreak, Pathogen, pathogenic, Research

Research – Biocontrol of multidrug resistant pathogens isolated from fish farms using silver nanoparticles combined with hydrogen peroxide insight to its modulatory effect

Posted on April 13, 2024 by | Leave a comment

Nature

This study was divided into two parts. The first part involved the isolation, and detection of the prevalence and antimicrobial resistance profile of Aeromonas hydrophila, Pseudomonas aeruginosa, and Vibrio species from Nile tilapia fish and marine aquatic water. One hundred freshly dead Nile tilapia fish were collected from freshwater aquaculture fish farms located in Al-Abbassah district, Sharkia Governorate, and 100 samples of marine aquatic water were collected from fish farms in Port Said. The second part of the study focused on determining the in vitro inhibitory effect of dual-combination of AgNPs-H2O2 on bacterial growth and its down regulatory effect on crucial virulence factors using RT-PCR. The highest levels of A. hydrophila and P. aeruginosa were detected in 43%, and 34% of Nile tilapia fish samples, respectively. Meanwhile, the highest level of Vibrio species was found in 37% of marine water samples. Additionally, most of the isolated A. hydrophila, P. aeruginosa and Vibrio species exhibited a multi-drug resistance profile. The MIC and MBC results indicated a bactericidal effect of AgNPs-H2O2. Furthermore, a transcriptional modulation effect of AgNPs-H2O2 on the virulence-associated genes resulted in a significant down-regulation of aerA, exoU, and trh genes in A. hydrophila, P. aeruginosa, and Vibrio spp., respectively. The findings of this study suggest the effectiveness of AgNPs-H2O2 against drug resistant pathogens related to aquaculture.

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Posted in Aeromonas, antimicrobial resistance, Antimicrobials, Emerging Pathogen, Food Pathogen, Pathogen, pathogenic, Pseudomonas aeruginosa, Vibrio, Vibrio cholera, Vibrio parahaemolyticus, Vibrio vulnificus

Research – Differences in Biofilm Formation of Listeria monocytogenes and Their Effects on Virulence and Drug Resistance of Different Strains

Posted on April 6, 2024 by | Leave a comment

MDPI

Abstract

Listeria monocytogenes is recognized as one of the primary pathogens responsible for foodborne illnesses. The ability of L. monocytogenes to form biofilms notably increases its resistance to antibiotics such as ampicillin and tetracycline, making it exceedingly difficult to eradicate. Residual bacteria within the processing environment can contaminate food products, thereby posing a significant risk to public health. In this study, we used crystal violet staining to assess the biofilm-forming capacity of seven L. monocytogenes strains and identified ATCC 19112 as the strain with the most potent biofilm-forming. Subsequent fluorescence microscopy observations revealed that the biofilm-forming capacity was markedly enhanced after two days of culture. Then, we investigated into the factors contributing to biofilm formation and demonstrated that strains with more robust extracellular polymer secretion and self-agglutination capabilities exhibited a more pronounced ability to form biofilms. No significant correlation was found between surface hydrophobicity and biofilm formation capability. In addition, we found that after biofilm formation, the adhesion and invasion of cells were enhanced and drug resistance increased. Therefore, we hypothesized that the formation of biofilm makes L. monocytogenes more virulent and more difficult to remove by antibiotics. Lastly, utilizing RT-PCR, we detected the expression levels of genes associated with biofilm formation, including those involved in quorum sensing (QS), flagellar synthesis, and extracellular polymer production. These genes were significantly upregulated after biofilm formation. These findings underscore the critical relationship between extracellular polymers, self-agglutination abilities, and biofilm formation. In conclusion, the establishment of biofilms not only enhances L. monocytogenes’ capacity for cell invasion and adhesion but also significantly increases its resistance to drugs, presenting a substantial threat to food safety.

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Posted in Biofilm, Food Microbiology Research, Food Pathogen, Listeria, Listeria monocytogenes, Pathogen, pathogenic, Research

Research – Surveillance and source tracking of foodborne pathogens in the vegetable production systems of India

Posted on March 20, 2024 by | Leave a comment

Science Direct

Abstract

Fresh vegetables are prone to foodborne pathogen infection due to improper cultivation methods and poor post-harvest handling practices. This paper describes the prevalence of foodborne pathogens in three vegetables (tomato, brinjal, and lablab) cultivated by small-scale producers of India. We assessed the possible entry of pathogens into the vegetable production chain. Samples from soil, manure, irrigation water, harvesting bins, and workers’ hands were assessed as sources of possible pathogen entry. In addition, further sampling was done to determine prevalence of these pathogens in the produce from the agricultural fields and markets. Total plate counts, yeast and mold count, total coliforms like general microbial indices, and possible foodborne pathogens like Salmonella, Escherichia coli O157, Staphylococcus aureus, Pseudomonas aeruginosa, and Norovirus were assessed in all the samples by standard microbiological, biochemical, and molecular methods. The results revealed that among the three vegetables we studied, brinjal had the highest load of general microbial indicators. Moreover, the total coliforms count of market vegetables was higher than that of on-farm vegetables, indicating poor hygiene in post-harvest operations. The pathogen Pseudomonas aeruginosa was found in the market tomatoes (0.35 log10 cfu/g), and E. coli was detected in the market samples of brinjal (2.98–3.89 log10 cfu/g) and lablab (0.59–2.21 log10 cfu/g), thereby revealing fecal cross-contamination during pre or post-harvest operations. None of the vegetable samples were contaminated with E. coli O157:H7, Staphylococcus aureus, Salmonella sp., and norovirus. However, the microbiological source tracking of primary production farms showed that E. coli O157:H7 was present in manure (9/27), soil (6/27), harvest bins (6/27), and irrigation water samples (3/27) of SSP farms. In addition, soil (33%), manure (11%), and harvest bins (11%) had Pseudomonas aeruginosa. In conclusion, our study suggests that adequate knowledge of good agricultural practices for small-scale producers to cultivate microbiologically safe vegetable production and proper handling strategies for vegetable vendors is crucial to mitigate foodborne pathogen outbreaks through fresh vegetables.

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Posted in Coliforms, E.coli O157, E.coli O157:H7, Food Microbiology Research, Food Pathogen, mold, Mould/Mold, Norovirus, Pathogen, pathogenic, Pseudomonas, Pseudomonas aeruginosa, Research, Salmonella, TVC

Research – Genomic surveillance of STEC/EHEC infections in Germany 2020 to 2022 permits insight into virulence gene profiles and novel O-antigen gene clusters

Posted on March 18, 2024 by | Leave a comment

Science Direct

Abstract

Shiga toxin-producing E. coli (STEC), including the subgroup of enterohemorrhagic E. coli (EHEC), are important bacterial pathogens which cause diarrhea and the severe clinical manifestation hemolytic uremic syndrome (HUS). Genomic surveillance of STEC/EHEC is a state-of-the-art tool to identify infection clusters and to extract markers of circulating clinical strains, such as their virulence and resistance profile for risk assessment and implementation of infection prevention measures. The aim of the study was characterization of the clinical STEC population in Germany for establishment of a reference data set. To that end, from 2020 to 2022 1257 STEC isolates, including 39 of known HUS association, were analyzed and lead to a classification of 30.4 % into 129 infection clusters. Major serogroups in all clinical STEC analyzed were O26, O146, O91, O157, O103, and O145; and in HUS-associated strains were O26, O145, O157, O111, and O80. stx1 was less frequently and stx2 or a combination of stx, eaeA and ehxA were more frequently found in HUS-associated strains. Predominant stx gene subtypes in all STEC strains were stx1a (24 %) and stx2a (21 %) and in HUS-associated strains were mainly stx2a (69 %) and the combination of stx1a and stx2a (12.8 %). Furthermore, two novel O-antigen gene clusters (RKI6 and RKI7) and strains of serovars O45:H2 and O80:H2 showing multidrug resistance were detected. In conclusion, the implemented surveillance tools now allow to comprehensively define the population of clinical STEC strains including those associated with the severe disease manifestation HUS reaching a new surveillance level in Germany.

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Posted in E.coli O103, E.coli O145, E.coli O157, E.coli O157:H7, E.coli O26, E.coli O26 :H11, eae, EHEC, Emerging Pathogen, Enterohaemorrhagic Escherichia coli, Food Pathogen, Haemolytic Uremic Syndrome, HUS, O103, O146, Pathogen, pathogenic, STEC, STEC E.coli, STX 1, STX 2

Research – Outbreaks hit record high in France in 2022

Posted on February 27, 2024 by | Leave a comment

Food Poison Journal

France reported a record high number of foodborne outbreaks in 2022, according to recently released data.

Notified outbreaks were at their highest since the start of surveillance in 1987 and continued the upward trend observed before the COVID-19 pandemic.

In 2022, 1,924 outbreaks were declared, affecting 16,763 people, of whom 643 went to hospital, and 17 died, said Santé publique France.

For 376 outbreaks, a pathogen could be confirmed in the food or in at least one sick person. A pathogen was suspected without microbiological confirmation for 1,260 outbreaks. For 288 outbreaks, no infectious agent was identified or suspected.

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Posted in food bourne outbreak, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, foodborne outbreak, foodbourne outbreak, microbial contamination, Microbial growth, Microbial Spoilage, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, outbreak, Pathogen, pathogenic

Research – Campylobacter presence on Dutch broiler farms and associated risk factors

Posted on February 25, 2024 by | Leave a comment

Science Direct

ABSTRACT

Campylobacter is the most reported zoonotic pathogen in humans in the European Union. Poultry is a major source of human infection with Campylobacter. Although many studies are done on the presence of Campylobacter in broilers and theoretically effective control measures are known, their relative importance at broiler farms remains poorly understood. Therefore the aim of this study was to investigate the presence of Campylobacter on selected broiler farms in the Netherlands, to determine the moment of introduction, and associated risk factors. A longitudinal study on 25 broiler farms was carried out between June 2017 and December 2020. Fecal samples were collected weekly from 43 broiler houses. In total 497 flocks were sampled. Putative variables on flock and farm characteristics for a risk factor analysis were gathered through questionnaires. Risk factors associated with the presence of Campylobacter in a broiler flock were determined using regression models. In total 30% of the flocks included in the study were positive for Campylobacter. Factors associated with presence of Campylobacter at slaughter age included: season, mowing lawns and presence of agricultural side activities. While summer/autumn and mowing lawns were associated with an increase in Campylobacter presence in flocks, the farmer having agricultural side activities other than poultry production was associated with a decrease. Analysis of the age at which flocks first tested Campylobacter positive revealed that slower growing breeds became positive on average one week later compared to regular growers. This study revealed a delayed introduction of Campylobacter in slower grower versus regular grower broiler flocks reared indoors. In addition it confirmed importance of season as major risk factor. The relevance of mowing and preceding positive flocks as risk factors needs further investigation.

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Posted in Campylobacter, campylobacter coli, Campylobacter jejuni, Food Microbiology Research, Food Pathogen, Pathogen, pathogenic, Research, Zoonosis