Category Archives: Staphylococcus aureus

Research – Antimicrobial Potential of Plastic Films Incorporated with Sage Extract on Chicken Meat

Posted on November 18, 2021 by | Leave a comment

MDPI

The function of packaging is crucial in the maintenance of fresh meat product quality. This study aimed to assess the efficiency of six films added with coatings 2379L/220 and 2379L/221 (containing sage extracts) to inhibit Salmonella typhimurium, Staphylococcus aureus, and Escherichia coli, which showed that two of the six films had a significant effect. Additionally, the effects of the films on refrigerated skinless chicken breast meat were evaluated based on microbiological content, colour, weight loss, texture and pH. Four of the six films were examined could extend the storability of refrigerated chicken breast fillets for up to seven days. All six treated films improved the pH, colour stability, weight loss, and texture of the chicken fillets. Therefore, these findings suggested that the coatings containing sage extracts having different viscosities (2379L/220 and 2379L/221) were effective as antimicrobial adhesives in food packaging films and can be commercially applied in prolonging the storage of chicken breast meat without affecting their quality. View Full-Text

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Posted in Decontamination Microbial, E.coli, escherichia coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiology, Microbiology Investigations, Research, Salmonella, Salmonella in Chicken, Staphylococcus aureus

Food Safety – Another record quarter for international food safety network

Posted on November 16, 2021 by | Leave a comment

Food Safety News

A global food safety network was involved in 65 incidents from July to September, which is more than earlier this year.

It is the third successive quarter that events involving the International Food Safety Authorities Network (INFOSAN) have gone up, with 63 from April to June and 56 in the first quarter of this year.

Salmonella was part of 46 incidents involving a biological hazard followed by Listeria with 11. Next was E. coli with four, a couple each for Bacillus cereus, Hepatitis A, Norovirus and Vibrio parahaemolyticus and one each for Clostridium botulinum and Staphylococcus aureus.

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Posted in Bacillus cereus, Clostridium botulinum, E.coli, Food Microbiology Research, Food Safety, Food Safety Alert, Hepatitis A, Listeria, Listeria monocytogenes, Research, Salmonella, Staphylococcus aureus, Vibrio parahaemolyticus

RASFF Alert – Staphylococcus aureus – E.coli – TVC – Enterobacteriaceae – Chilled Noodles with Eggs

Posted on November 5, 2021 by | Leave a comment

RASFF

Coagulase-positive Staphylococcus (2300 CFU/g), too high count of aerobic mesophiles (210000000 CFU/g) and high counts of Enterobacteriaceae (18000000 CFU/g) and of Escherichia coli (5100 CFU/g) in chilled noodles with eggs from Slovakia in Austria

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Posted in E.coli, Enterobacteriaceae, food contamination, Food Hazard, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, Food Pathogen, Food Poisoning, food recall, Food Safety, Food Safety Alert, Food Testing, RASFF, Staphylococcus aureus, TVC

Research – The combined effect of green tea and peppermint oil against pathogenic bacteria to extend the shelf life of eggs at ambient temperature and the mode of action

Posted on October 29, 2021 by | Leave a comment

Wiley Online

This work investigated the antimicrobial activities of green tea (GT) at 5 and 10.0% wt/vol and peppermint oil (PP) at 0.1, 0.15, and 0.2% wt/vol against major pathogen bacteria (Escherichia coli, Salmonella enteritidis, and Staphylococcus aureus) found on eggs at room temperature (30°C). The quality factors (weight loss, Haugh unit, albumen pH, egg yolk, and albumen index) of treated eggs were also measured while they were stored at room temperature for 14 days. A 9-point hedonic scale was used for sensory evaluation. Scanning electron microscopy was used to examine the morphology of bacteria cells to understand this study’s mechanism of action. It was found that combining 10% GT and 0.15% PP had complete antibacterial activity against all pathogenic bacteria investigated, and could extend the shelf life of treated eggs from 7 days (control) to at least 14 days. The treated egg’s coliforms (≤3.0 log10 colony-forming unit [CFU] g−1), E. coli (≤1.8 log10 CFU g−1), TVC (≤4.3 log10 CFU g−1), Salmonella spp., (not detected in 25 g), and S. aureus (not detected in 25 g) were better able to meet the microbiological criteria for egg after 14 days of storage, when compared to the control, which exceeded the criteria within 7 days. In addition, consumers rated egg acceptability as favorable by giving a sensory score ranging from like slightly to like moderately (~6.7). Furthermore, when compared to the control (6–7 days), all treated eggs retained their quality during storage for 14 days and met the microbiological criteria for egg in food standard (<4.7–6.0 log10 CFU g−1 for total visible count). Compound leakage from within the bacteria, which was the mode of action when GT and PP were combined, resulted in a wrinkled appearance of bacteria cells and serious defects in bacteria membrane morphology. These findings suggest that a sanitizing spray derived from GT and PP can extend the shelf life of eggs and ensure their safety for human consumption at room temperature without using a refrigerator.

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Posted in Decontamination Microbial, E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Salmonella, Staphylococcus aureus, Technology

Research – Inactivation of Salmonella enterica serovar Typhimurium and Staphylococcus aureus in rice by radio-frequency heating 

Posted on October 8, 2021 by | Leave a comment

Journal of Food Protection

The objectives of this study were to determine the effect of the milling degree (MD) of Oryza sativa L. (Korean rice) on the heating rate, pathogen inactivation (Salmonella Typhimurium and Staphylococcus aureus), and color change resulting from radio-frequency (RF) heating. Rice samples inoculated with pathogens were placed in a polypropylene jar and subjected to RF heating for 0-75 s. The heating rate of rice with a 2% MD was the highest during RF heating, followed by those with a 0, 8, and 10% MD, and the reduction of pathogens showed the same trend. The reduction of the levels of pathogens in rice with a MD 0 and 2% was significantly higher than that observed for rice with a MD of 8 and 10% under the same treatment conditions. For example, log reductions of S. Typhimurium in rice by 55 s RF heating were 3.64, 5.19, 2.18, and 1.80 for milling degree of 0, 2, 8, and 10%, respectively. At the same treatment conditions, log reduction of S. aureus were 2.77, 5.08, 1.15, and 0.90 for milling degree of 0, 2, 8, and 10%, respectively. The color of rice measured according to L*, a*, and b* was not significantly altered after RF heating, regardless of the MD. Therefore, the MD of rice should be considered before RF heating is applied to inactivate foodborne pathogens.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Salmonella, Staphylococcus aureus, Technology

Research – Antimicrobial resistance, virulence , Antimicrobial resistance, virulence genes, and biofilm formation in Staphylococcus aureus strains isolated from meat and meat products

Posted on September 28, 2021 by | Leave a comment

Wiley Online

Staphylococcus aureus is an important food pathogen that has the ability to form biofilms. This pathogen has been implicated in foodborne outbreaks associated with the consumption of meat and meat products. Since the role of meat products as reservoirs of antimicrobial resistant S. aureus and biofilm formers has not been studied, this research was conducted to assess the incidence, antimicrobial resistance, and presence of biofilm-forming genes in S. aureus bacteria from meat and meat products. For this purpose, 440 samples of meat and meat products were randomly collected from supermarkets of Shahrekord city, Iran. S. aureus isolates were highlighted and identified through biochemical tests. All S. aureus isolates were profiled for susceptibility to 14 antibiotics and the corresponding resistance genes were searched. The quantification of biofilm formation followed by a screening of biofilm formation encoding genes was done. Of the 440 samples collected, 61 were found to contain S. aureus. The incidence of S. aureus among the beef meat (16/61) was the highest followed by its incidence in sausage (10/61) and lunch meat (9/61). At least one isolate of S. aureus carries one of the following resistance gene blaZ, mecA, tet K, linA, tetM, erm A, ermB, and aac A-D. High distribution of icaA, icaB, icaC, icaD, clfB, and clfA, biofilm formation genes and Enterotoxin encoding genes sea, seb, sec, and sed. The ability of biofilm production and the presence of virulence determinants in the genome of S. aureus can contribute to their pathogenicity. This research demonstrated the roles of meat and meat products as reservoirs of biofilm-forming and antimicrobial-resistant strains of S. aureus. This poses a food safety and public health problem. However, further work needs to be done to better understand the implication of icaABCD biofilm forming genes present in S. aureus from meat and meat products in their resistance.

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Posted in Biofilm, Enterotoxin, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Staphylococcus aureus

Research – Antimicrobial activity and mechanism of limonene against Staphylococcus aureus

Posted on August 28, 2021 by | Leave a comment

Wiley Online

Staph

In this study, inhibitory effect of limonene on Staphylococcus aureus (S. aureus) and its antibacterial mechanism was explored, respectively. The results showed that limonene effectively inhibited bacterial growth at a minimum inhibitory concentration (MIC) of 20 ml/L. Scanning electron microscopy (SEM), the reduction of AKP activity and fluorescence microscope observation confirmed that limonene caused the destruction of the cell morphology and cell wall integrity of S. aureus. The reduction of MFI in fluorescein diacetate staining experiment and leakage of biological macromolecules (nucleic acids and proteins) indicated that limonene damaged the cell membrane and increased membrane permeability. Besides, the reduction of membrane potential (MP) further confirmed that the damage to membrane and the reduction of respiratory metabolic activity. Furthermore, the respiratory depression test confirmed that the pathway of limonene affecting the respiratory metabolism of S. aureus is TCA pathway, followed by EMP. In addition, the disorder of succinate dehydrogenase (SDH), malate dehydrogenase (MDH), pyruvate kinase (PK), ATPase (T-ATPase, Na+-K+-ATPase, Ca2+-Mg2+-ATPase), and ATP concentration demonstrated that limonene could result in a slowdown of metabolism and metabolic dysfunction, thus inhibiting ATP synthesis.

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Posted in Food Microbiology Research, Research, Staphylococcus aureus

Research – Effects of Combined Aerosolization with Ultraviolet C Light-Emitting Diode on Enterohemorrhagic Escherichia coli and Staphylococcus aureus Attached to Soft Fresh Produce

Posted on August 18, 2021 by | Leave a comment

MDPI

Washing soft fresh produce such as strawberries, baby leaves, and sliced onions with sanitizing agents is challenging due to their fragile texture. Thus, treatments like aerosolization using slightly acidic electrolyzed water (SAEW) and ultraviolet C light-emitting diode (UVC LED) irradiation may be good alternatives. In the present study, the reduction effects of a combined treatment of aerosolization using SAEW and UVC LED irradiation on enterohemorrhagic Escherichia coli (EHEC) and Staphylococcus aureus attached to strawberries, baby leaves, and sliced onions were investigated. The behaviours of EHEC and S. aureus, moisture loss, colour measurement, and visual appearance were also analyzed at 10 and 15 °C for 7 days. The reduction effect of the combined treatment with 100 SAEW and UVC LED was higher (0.53–0.92 log CFU g−1) than a single aerosolization treatment (0.11–0.41 log CFU g−1), regardless of samples or pathogens. A greater effect on EHEC and S. aureus reduction was observed in strawberries (0.74 and 0.92 log CFU g−1) than in baby leaves (0.62 and 0.53 log CFU g−1) and sliced onions (0.55 and 0.62 log CFU g−1). The combined treatment further reduced the EHEC and S. aureus populations in strawberries during 7 days of storage at 10 and 15 °C. However, the EHEC and S. aureus populations were maintained in baby leaves and sliced onions at 10 °C for 7 days. Additionally, the greatest effect on the maintenance of colour and appearance was obtained in the combined treatment. Since the combined treatment reduces EHEC and S. aureus populations and preserves visual quality, it could be expected to extend the shelf life of soft fresh produce at the retailer stage of the supply chain. View Full-Text

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Posted in E.coli, EHEC, escherichia coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Staphylococcus aureus, UV Microbiology

Research – Antimicrobial Efficacy and Spectrum of Phosphorous-Fluorine Co-Doped TiO2 Nanoparticles on the Foodborne Pathogenic Bacteria Campylobacter jejuni, Salmonella Typhimurium, Enterohaemorrhagic E. coli, Yersinia enterocolitica, Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus

Posted on August 8, 2021 by | Leave a comment

MDPI

Contamination of meats and meat products with foodborne pathogenic bacteria raises serious safety issues in the food industry. The antibacterial activities of phosphorous-fluorine co-doped TiO2 nanoparticles (PF-TiO2) were investigated against seven foodborne pathogenic bacteria: Campylobacter jejuni, Salmonella Typhimurium, Enterohaemorrhagic E. coli, Yersinia enterocolitica, Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus. PF-TiO2 NPs were synthesized hydrothermally at 250 °C for 1, 3, 6 or 12 h, and then tested at three different concentrations (500 μg/mL, 100 μg/mL, 20 μg/mL) for the inactivation of foodborne bacteria under UVA irradiation, daylight exposure or dark conditions. The antibacterial efficacies were compared after 30 min of exposure to light. Distinct differences in the antibacterial activities of the PF-TiO2 NPs, and the susceptibilities of tested foodborne pathogenic bacterium species were found. PF-TiO2/3 h and PF-TiO2/6 h showed the highest antibacterial activity by decreasing the living bacterial cell number from ~106 by ~5 log (L. monocytogenes), ~4 log (EHEC), ~3 log (Y. enterolcolitca, S. putrefaciens) and ~2.5 log (S. aureus), along with complete eradication of C. jejuni and S. Typhimurium. Efficacy of PF-TiO2/1 h and PF-TiO2/12 h NPs was lower, typically causing a ~2–4 log decrease in colony forming units depending on the tested bacterium while the effect of PF-TiO2/0 h was comparable to P25 TiO2, a commercial TiO2 with high photocatalytic activity. Our results show that PF-co-doping of TiO2 NPs enhanced the antibacterial action against foodborne pathogenic bacteria and are potential candidates for use in the food industry as active surface components, potentially contributing to the production of meats that are safe for consumption. View Full-Text

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Posted in Campylobacter, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Technology, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Salmonella, Shewanella, Staphylococcus aureus, Technology, Yersinia, yersinia enterocolitica

Research – Antimicrobial Efficacy and Spectrum of Phosphorous-Fluorine Co-Doped TiO2 Nanoparticles on the Foodborne Pathogenic Bacteria Campylobacter jejuni, Salmonella Typhimurium, Enterohaemorrhagic E. coli, Yersinia enterocolitica, Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus

Posted on August 7, 2021 by | Leave a comment

MDPI

Yersinia p

Contamination of meats and meat products with foodborne pathogenic bacteria raises serious safety issues in the food industry. The antibacterial activities of phosphorous-fluorine co-doped TiO2 nanoparticles (PF-TiO2) were investigated against seven foodborne pathogenic bacteria: Campylobacter jejuni, Salmonella Typhimurium, Enterohaemorrhagic E. coli, Yersinia enterocolitica, Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus. PF-TiO2 NPs were synthesized hydrothermally at 250 °C for 1, 3, 6 or 12 h, and then tested at three different concentrations (500 μg/mL, 100 μg/mL, 20 μg/mL) for the inactivation of foodborne bacteria under UVA irradiation, daylight exposure or dark conditions. The antibacterial efficacies were compared after 30 min of exposure to light. Distinct differences in the antibacterial activities of the PF-TiO2 NPs, and the susceptibilities of tested foodborne pathogenic bacterium species were found. PF-TiO2/3 h and PF-TiO2/6 h showed the highest antibacterial activity by decreasing the living bacterial cell number from ~106 by ~5 log (L. monocytogenes), ~4 log (EHEC), ~3 log (Y. enterolcolitca, S. putrefaciens) and ~2.5 log (S. aureus), along with complete eradication of C. jejuni and S. Typhimurium. Efficacy of PF-TiO2/1 h and PF-TiO2/12 h NPs was lower, typically causing a ~2–4 log decrease in colony forming units depending on the tested bacterium while the effect of PF-TiO2/0 h was comparable to P25 TiO2, a commercial TiO2 with high photocatalytic activity. Our results show that PF-co-doping of TiO2 NPs enhanced the antibacterial action against foodborne pathogenic bacteria and are potential candidates for use in the food industry as active surface components, potentially contributing to the production of meats that are safe for consumption.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Listeria, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Shewanella, Staphylococcus aureus, UV Microbiology, Yersinia, yersinia enterocolitica