Category Archives: Staphylococcus aureus

Research – Plant Extract and Essential Oil Application against Food-Borne Pathogens in Raw Pork Meat

Posted on April 1, 2022 by | Leave a comment

MDPI

Herbal and plant extracts are being applied for a wide range of foods against different types of food-borne pathogens. In the present study, ethanolic and aqueous extracts (2% w/v) from cranberry (Vaccinium macrocarpon) and pomegranate (Punica granatum L.) plants were applied alone or in combination with two essential oils (thyme and oregano in a concentration of 0.150 μg/g) in pork meatballs and their antimicrobial activity was estimated. The extracts exhibited promising results (aqueous and ethanolic extracts of pomegranate and cranberry in a food-compatible concentration of 2% w/v) were applied to raw pork meatball production and their antimicrobial activity was recorded versus Enterobacteriaceae, total mesophilic bacteria, yeasts/molds, Staphylococcus spp., Pseudomonas spp. and lactic acid bacteria (LAB). The outcome demonstrated that meatballs containing aqueous extracts of pomegranate were more resistant to spoilage compared to all the other samples since they were preserved for more days. The chemical profiles of plant extracts were determined through LC-QTOF/MS and the chemical composition of the essential oils applied was determined with the use of GC/MS in order to identify the substances involved in the observed antimicrobial activity. Phenolic acids (quinic acid, chlorogenic acid), monoterpenes (p-cymene, carvacrol, thymol, limonene), organic acids (citric acid) and phenols were the main constituents found in the plant extracts and essential oils applied. These extracts of plant origin could be used as natural preservatives in meat products, even in low concentrations. View Full-Text

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Posted in Decontamination Microbial, Enterobacteriaceae, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, lactic acid bacteria, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Pseudomonas, Research, Staphylococcus aureus

Research – Enhanced antimicrobial effectiveness of synergistic mixtures of rambutan peel extract and cinnamon essential oil on food spoilage bacteria and bio-based food packaging

Posted on March 31, 2022 by | Leave a comment

Wiley Online

Staph

This research aims to enhance antimicrobial activity of rambutan peel extract (RPE), by mixing with cinnamon essential oil (CEO). The mixture of RPE and CEO with different weight ratios (10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9, and 0:10) had been prepared and the antimicrobial efficacy was tested. Nine strains of bacteria: Gram-positive bacteria (Bacillus sp., Enterococcus faecalis, Leuconostoc sp., Micrococcus luteus, Staphylococcus aureus, and Streptococcus sp.) and Gram-negative bacteria (Escherichia coli, Pseudomonas fluorescens, and Salmonella typhimurium) were selected as the representative of pathogenic and food spoilage bacteria. Mixing RPE with CEO in a ratio of 5:5 showed the best synergistic effect against those bacteria. Addition of RPE/CEO in a weight ratio of 5:5 improved the antimicrobial activity of whey protein isolated (WPI) films, and enhanced strength, stiffness, and water resistance of the film.

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

Research – Spain – Report of the Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN) on the safety of foods air-dried outdoors that are produced by traditional methods and which require an adjustment of the hygiene requirements that must be fulfilled

Posted on February 13, 2022 by | Leave a comment

AESAN

Abstract
The European Union recognises that traditional methods of food production are a valuable and irreplaceable heritage that must be preserved over time. Therefore, Regulation (EC) No. 852/2004 permits a degree of flexibility in its application provided food hygiene goals are not compromised. For decades, both plant and animal-based foods have been produced in Spain which are air-dried outdoors until reaching a low water activity (aw) that enables their preservation at room temperature. These foods include, raisins, dried apricots, dried figs, ñora peppers, dried fish or octopus that are at least partially air-dried, among others.
The Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN) is of the opinion that the processing of naturally dried foods leads to their correct preservation, provided they reach an aw that inhibits the proliferation of pathogenic microorganisms and the production of toxins in them. Some of the stages in the process may cause microbial inactivation.
Above all, it is necessary to ensure the absence of the formation of toxins, with aflatoxins being the ones that have been most frequently identified. Thus, it is considered that the drying should be conducted in the least time possible, ensuring a decrease of aw within the first 2-3 days of below 0.90 to inhibit the development of aflatoxins, and this drying should be continued until aw levels lower than 0.70 are reached, preventing the growth of pathogenic microorganisms that cause spoilage. It is necessary to guarantee suitable hygienic conditions during processing in order to prevent contamination by pathogens and/or toxins.
Although they cannot proliferate in the stated preservation conditions, they can remain viable in the final product, therefore they may pose a risk to consumer health. Microorganisms with a low infective dose and those that have been identified in dried products (such as S. aureus and Salmonella) and microbial toxins are especially relevant. Autonomous Communities must monitor compliance with the requirements to ensure that they do not pose a risk in these products.
Although these types of products have a low aw, within the range of 0.6 to 0.8 according to avail-able literature, given that this information is not available for each assessed product, the level of safety reached cannot be established on an individual basis. Additionally, the diverse factors used in some of them (additives and preservatives, pasteurisation processes, etc.) require individual assessment once all the necessary information is available. Therefore, the drying must reach aw levels below 0.70 in the least time possible for these types of products to be considered stable, as given these conditions, there is no scientific evidence that shows that the safety and stability of the dried products are compromised, provided good hygiene practices are maintained during their preservation and storage.
For final levels of aw that are higher, correct preservation may be achieved through a combination of factors which proves that it is effective throughout the shelf life of the product, maintaining the aforementioned appropriate hygiene practices.

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Posted in Aflatoxin, Available Water, aW, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Pathogen, pathogenic, Research, Salmonella, Staphylococcus aureus, water activity

Slovakia – Report on zoonoses, foodborne diseases and waterborne diseases in the Slovak Republic in 2020

Posted on January 17, 2022 by | Leave a comment

MPSR

 

The protection of human and animal health can only be achieved through the active cooperation of experts in the field of control and research in the human and veterinary field. The report on zoonoses, foodborne diseases and waterborne diseases in the Slovak Republic for 2020 contains data from official inspections carried out in the field of agriculture and health care, as well as from research institutes and universities. The preparation of the report was coordinated by the National Contact Point for Scientific and Technical Cooperation with the European Food Safety Authority (EFSA EFSA), which is established at the Department of Food Safety and Nutrition of the Ministry of Agriculture and Rural Development of the Slovak Republic (MPRV SR).

The report serves as a basis for the EFSA NCB and scientific experts to set priorities and own national food safety risk assessments. At the same time, the report serves as one of the bases for the Community risk assessment carried out by the European Food Safety Authority (EFSA). Scientific risk assessment is the basis for risk management. The report describes the situation in  35 zoonotic agents, 5 foodborne diseases (ie foodborne diseases) without zoonotic potential and 4 waterborne pathogens. Of the 44 agents monitored, 23 are bacterial, 10 parasitic, 10 viral and prion.

It presents the summary results of examinations and tests performed in 2020 in the Slovak Republic and the evaluation of the national epidemiological situation in humans and animals with a focus on trends and sources of zoonotic and foodborne diseases.

The report presents the summary results of examinations and tests carried out in 2020 and an assessment of the national epidemiological situation in humans and animals , focusing on trends and sources of zoonotic and foodborne diseases . The number of monitored authors, cooperating organizations and experts is growing every year. A wide team of more than 70 experts from 24 scientific and control organizations in the Slovak Republic took part in its elaboration .

In 2020, 17,067 human diseases caused by the study agents were reported, with 29.1% related to campylobacteriosis, 20.9% to Clostridium dificille and 20.4% to salmonellosis. Rotavirus 11.6%, Norwalk virus 5.1%, Borrelia burgdorferi sl 5.6% and  Escherichia coli 1.2% also contributed to a higher percentage of diseases.

Seven of the study agents caused 380 human epidemics, of which 56.6% were salmonellosis, 23.2% were campylobacteriosis and 12.6% of epidemics were caused by rotavirus. Norwalk virus accounted for 5.5%, tick-borne encephalitis virus 1.3%, shigella and 0.5% and yersinia 0.3%.  

35,957 food samples were examined for the presence of 15 pathogens with a positive finding in 2.2% of samples. Higher percentages of positive findings were in  Yersinia spp. 48.1%, Enterococcus spp. 46.3% and  Vibrio spp. 31.8%.

The presence of 30 pathogens was monitored in 2,483,239 samples originating from livestock and wild animals, pets and zoos taken as part of official control, preventive monitoring, research, as well as from sick or dead animals. Positive findings accounted for 0.1% of samples. Higher percentages of positive findings were recorded for  Aeromonas spp. 59.3%, Clostridium spp. 55.4%, Francisella tularensis 50.4%, Babesia spp. 41.1%, Dirofilaria spp. 34.8%, Campylobacter spp. 18.3%, Yersinia spp. 18.3%, Staphylococcus aureus 18.1%, hepatitis E virus 14.1%, Listeria monocytogenes  11.8%, Toxocara spp. 10.5%.

Feed – 385 samples were examined for the presence of Salmonella spp. (1.5% positive samples), Escherichia coli (60.0% positive samples) and Clostridium spp.

(1.7% positive samples).

35,746 water samples were examined for the presence of 9 agents, of which 7.4% were positive, of which Legionella spp. 47.1% and Vibrio spp. 39.5%.

44,633 samples from the environment were examined for the presence of 8 pathogens, of which 2.3% were positive, of which Legionella spp. 36.0%, Vibrio spp. 6.8%,  E.coli 3.6% and  Enterococcus spp. 2.6%.

The report also includes the results of examinations for the resistance of microorganisms to antimicrobials, which has a growing trend worldwide and poses a real danger in the treatment of infections. Microbial resistance was monitored in Salmonella spp., E. coli , Campylobacter spp., Staphylococcus aureus and  Enterococcus spp.

The comprehensive report, which will be published as a publication, has a length of more than 130 pages, will be published in printed form, as a publication with an assigned ISBN. Summaries of individual chapters will be translated into English and published in an electronic version as a publication with an assigned ISBN.

See the appendices for more information.

Attachments (downloadable documents)

 

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Posted in Aeromonas, Campylobacter, Clostridium, Clostridium difficile, Enterococcus, escherichia coli, Hepatitis E, Legionella, Legionnaires’ disease, Listeria, Listeria monocytogenes, Rotavirus, Salmonella, Staphylococcus aureus, Vibrio, Yersinia, yersinia enterocolitica, Zoonosis

Research – Evaluation of microbial contamination in cold dishes and Prevalence of food-borne pathogens in the Jilin Province

Posted on January 6, 2022 by | Leave a comment

Journal of Food Protection

In this study, we evaluated the microbial contamination status of cold dishes consumed by residents of Jilin Province and investigated to determine the incidence of four pathogenic bacteria in cold dishes. A total of 300 samples of cold dishes including meat, vegetable and mixed products, were collected from three different purchasing places: supermarkets, farmers’ markets and mobile vendors. Live bacteria were isolated using conventional culture methods. After separation, a quick and easy polymerase chain reaction (PCR) was used to detect Listeria monocytogenes , Staphylococcus aureus , Enterotoxic Escherichia coli and Salmonella . The results showed that the total number of microbial colonies in the vegetable samples exceeded the standard rate of 8%, and the total number of microbial colonies in the meat and mixed samples did not exceed the standard. The total microbial colony count exceeded the standard in all three different procurement sites, with the highest exceedance of 7.4% in the mobile vendor sites. The detection rates of Enterotoxigenic Escherichia coli , Staphylococcus aureus , L. monocytogenes and Salmonella among the four pathogenic bacteria detected in all samples were 4.3%, 3.3%; 3.0%; and 1.0%, respectively. This study can be used to qualitatively assess the microbiological quality associated with cold dishes. It provides data to support the detection of possible food safety problems.

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Posted in Decontamination Microbial, E.coli, 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, Salmonella, Staphylococcus aureus, STEC, STEC E.coli

Research – A Naturally Derived Nanocomposite Film with Photodynamic Antibacterial Activity: New Prospect for Sustainable Food Packaging

Posted on December 30, 2021 by | Leave a comment

ACS

Abstract Image

Food packaging with efficient antibacterial ability is highly desirable and challenging in facing the crisis of microbial contamination. However, most present packaging is based on metal-based antibacterial agents and requires a time-consuming antibacterial process. Here, the unique packaging (CC/BB films) featuring aggregation-induced emission behavior and photodynamic inactivation activity is prepared by dispersing self-assembled berberine–baicalin nanoparticles (BB NPs) into a mixed matrix of sodium carboxymethylcellulose-carrageenan (CC). The superiority of this design is that this packaging film can utilize sunlight to generate reactive oxygen species, thus eradicating more than 99% of E. coli and S. aureus within 60 min. Also, this film can release BB NPs to inactivate bacteria under all weather conditions. Surprisingly, the CC/BB nanocomposite film presented excellent mechanical performances (29.80 MPa and 38.65%), hydrophobicity (117.8°), and thermostability. The nanocomposite film is validated to be biocompatible and effective in protecting chicken samples, so this work will provide novel insights to explore safe and efficient antibacterial food packaging.

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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, Staphylococcus aureus, Technology

Research – Role of blue light in bactericidal effect against meat-borne pathogens and freshness maintaining of beef 

Posted on December 18, 2021 by | Leave a comment

Journal of Food Protection

Beef is rich in various nutrients while easily spoils due to contamination by pathogens, thus it is of great significance to develop a bactericidal method to inactivate meat-borne pathogens and meanwhile maintain the freshness of beef. For the first time, the present study investigated the bactericidal effect of blue light (BL) at 415 nm against four meat-borne pathogens (methicillin-resistant Staphylococcus aureus , Escherichia coli , Salmonella Typhimurium and Listeria monocytogenes ) in vitro and inoculated on the surface of fresh beef, respectively. When the non-illuminated beef was used as control, the population of the four pathogens did not change significantly ( P > 0.05), while BL-illuminated beef showed dose-dependent inactivation effect in both in vitro and in vivo studies. The experiments on beef cuts showed that 109.44 J/cm 2 of BL inactivated 90% of inoculated cells for the tested strains ( P < 0.05), and the impact of BL inactivation could be sustained in 7 days of cold storage. Notably, changes of lipid oxidation rate, water holding capacity and cooking loss value between the control and beef illuminated by 109.44 J/cm 2 at the same time were scarcely detected during the storage. BL had a minor but insignificant influence on surface color and free amino acid content. Moreover, the pH of illuminated beef increased slower ( P < 0.05) than that of non-illuminated beef. The present work demonstrated that BL could be a novel bactericidal and freshness-maintaining method for fresh beef.

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

Research – Effect of Plasma-Activated Solution Treatment on Cell Biology of Staphylococcus aureus and Quality of Fresh Lettuces

Posted on December 12, 2021 by | Leave a comment

MDPI

This study aimed to investigate effects of plasma-activated solution (PAS) on the cell biology of Staphylococcus aureus and qualities of fresh lettuce leaves. PAS was prepared by dielectric barrier discharge plasma and incubated with S. aureus for 10–30 min or with lettuces for 10 min. Effects on cell biology were evaluated with microscopic images, cell integrity, and chemical modification of cellular components. Effects on lettuce quality were estimated with the viable microbial counts, color, contents of vitamin C and chlorophyll, and surface integrity. PAS reduced S. aureus population by 4.95-log and resulted in increased cell membrane leakage. It also resulted in increased contents of reactive oxygen species in cells, C=O bonds in peptidoglycan, and 8-hydroxydeoxyguanosine content in cellular DNA, and reduced ratios of unsaturated/saturated fatty acids in the cell membrane. PAS treatment reduced bacterial load on fresh lettuce and had no negative effects on the quality. Data suggest that PAS can be used for the disinfection of ready-to-eat fresh vegetables. View Full-Text

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

Research – Uses of Bacteriophages as Bacterial Control Tools and Environmental Safety Indicators

Posted on December 2, 2021 by | Leave a comment

Frontiers in Microbiology

Bacteriophages are bacterial-specific viruses and the most abundant biological form on Earth. Each bacterial species possesses one or multiple bacteriophages and the specificity of infection makes them a promising alternative for bacterial control and environmental safety, as a biotechnological tool against pathogenic bacteria, including those resistant to antibiotics. This application can be either directly into foods and food-related environments as biocontrol agents of biofilm formation. In addition, bacteriophages are used for microbial source-tracking and as fecal indicators. The present review will focus on the uses of bacteriophages like bacterial control tools, environmental safety indicators as well as on their contribution to bacterial control in human, animal, and environmental health.

Introduction

Bacteriophages, also known as phages, are prokaryotes viruses, being the most abundant life form, present in all environments and the predominant entities in the sea (Boehme, 1993; Suttle, 2005). Several studies have demonstrated a 1:5 relative abundance between bacteria and bacteriophage (Fuhrman, 1999; Balter, 2000; Rohwer, 2003). They were discovered independently by Twort (1915), who isolated them from Staphylococcus spp., and from patients with dysentery. D’Herelle (1926) described bacteriophage as a virus that has the capability to parasitize bacteria (Twort, 1915; Delbruck, 1942). Bacteriophages vary greatly in morphology and replicative characteristics, containing either RNA or DNA, being these parameters currently used by the International Committee on Taxonomy of Viruses (ICTV) for bacteriophage classification (King et al., 2012; Table 1). However, the identification of bacteriophages is difficult since there are no universally conserved markers, unlike e.g., the bacterial 16S rRNA gene (Paul et al., 2002), with only minor parts of bacteriophage genomes being used to determine family specific makers, such as the viral capsid g20 of T4 (Fuller et al., 1998; Marston and Sallee, 2003; Sullivan et al., 2008).

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Posted in Bacteriophage, 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, Technology

Research – Ultrashort-pulse lasers kill bacterial superbugs, spores

Posted on November 27, 2021 by | Leave a comment

Science Daily

Life-threatening bacteria are becoming ever more resistant to antibiotics, making the search for alternatives to antibiotics an increasingly urgent challenge. For certain applications, one alternative may be a special type of laser.

Researchers at Washington University School of Medicine in St. Louis have found that lasers that emit ultrashort pulses of light can kill multidrug-resistant bacteria and hardy bacterial spores. The findings, available online in the Journal of Biophotonics, open up the possibility of using such lasers to destroy bacteria that are hard to kill by other means. The researchers previously have shown that such lasers don’t damage human cells, making it possible to envision using the lasers to sterilize wounds or disinfect blood products.

“The ultrashort-pulse laser technology uniquely inactivates pathogens while preserving human proteins and cells,” said first author Shaw-Wei (David) Tsen, MD, PhD, an instructor of radiology at Washington University’s Mallinckrodt Institute of Radiology (MIR). “Imagine if, prior to closing a surgical wound, we could scan a laser beam across the site and further reduce the chances of infection. I can see this technology being used soon to disinfect biological products in vitro, and even to treat bloodstream infections in the future by putting patients on dialysis and passing the blood through a laser treatment device.”

Tsen and senior author Samuel Achilefu, PhD, the Michel M. Ter-Pogossian Professor of Radiology and director of MIR’s Biophotonics Research Center, have been exploring the germicidal properties of ultrashort-pulse lasers for years. They have shown that such lasers can inactivate viruses and ordinary bacteria without harming human cells. In the new study, conducted in collaboration with Shelley Haydel, PhD, a professor of microbiology at Arizona State University, they extended their exploration to antibiotic-resistant bacteria and bacterial spores.

The researchers trained their lasers on multidrug-resistant Staphylococcus aureus (MRSA), which causes infections of the skin, lungs and other organs, and extended spectrum beta-lactamase-producing Escherichia coli (E. coli), which cause urinary tract infections, diarrhea and wound infections. Apart from their shared ability to make people miserable, MRSA and E. coli are very different types of bacteria, representing two distant branches of the bacterial kingdom. The researchers also looked at spores of the bacterium Bacillus cereus, which causes food poisoning and food spoilage. Bacillus spores can withstand boiling and cooking.

In all cases, the lasers killed more than 99.9% of the target organisms, reducing their numbers by more than 1,000 times.

Viruses and bacteria contain densely packed protein structures that can be excited by an ultrashort-pulse laser. The laser kills by causing these protein structures to vibrate until some of their molecular bonds break. The broken ends quickly reattach to whatever they can find, which in many cases is not what they had been attached to before. The result is a mess of incorrect linkages inside and between proteins, and that mess causes normal protein function in microorganisms to grind to a halt.

“We previously published a paper in which we showed that the laser power matters,” Tsen said. “At a certain laser power, we’re inactivating viruses. As you increase the power, you start inactivating bacteria. But it takes even higher power than that, and we’re talking orders of magnitude, to start killing human cells. So there is a therapeutic window where we can tune the laser parameters such that we can kill pathogens without affecting the human cells.”

Heat, radiation and chemicals such as bleach are effective at sterilizing objects, but most are too damaging to be used on people or biological products. By inactivating all kinds of bacteria and viruses without damaging cells, ultrashort-pulse lasers could provide a new approach to making blood products and other biological products safer.

“Anything derived from human or animal sources could be contaminated with pathogens,” Tsen said. “We screen all blood products before transfusing them to patients. The problem is that we have to know what we’re screening for. If a new blood-borne virus emerges, like HIV did in the ’70s and ’80s, it could get into the blood supply before we know it. Ultrashort-pulse lasers could be a way to make sure that our blood supply is clear of pathogens both known and unknown.”

Story Source:

Materials provided by Washington University School of Medicine. Original written by Tamara Bhandari. Note: Content may be edited for style and length.

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Posted in Bacillus, Bacillus cereus, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, Food Virus, microbial contamination, Microbiological Risk Assessment, Microbiology, MRSA, Research, Staphylococcus aureus, Technology