Category Archives: Staphylococcus aureus

Research – In vitro antimicrobial effects of Myristica fragrans essential oil on foodborne pathogens and its influence on beef quality during refrigerated storage

Wiley Online

Nutmeg (Myristica fragrans) seed was subjected to the hydro‐distillation method to extract its essential oil (NEO). Its main constituents were α‐pinene (20.16%), sabinene (14.45%), and β‐pinene (13.26%) with great antimicrobial and antioxidant actions. A novel edible coating was then fabricated based on the sage seed mucilage (SSM) and NEO, to ameliorate the quality and shelf‐life of beef slices. The NEO‐loaded SSM coating was able to significantly decrease the population of total viable count, Escherichia coliStaphylococcus aureus, psychrotrophic bacteria, and fungi. Moreover, lipid oxidation of beef slices was remarkably suppressed upon the application of bioactive NEO‐loaded SSM edible coating, as compared with the control by Day 6. The coated beef sample, especially NEO‐rich SSM coated ones perceived a higher consumer acceptance and firmness than the SSM coated and noncoated samples. The SSM edible coating containing NEO could therefore have the potential to control the growth of pathogenic microorganisms and lipid oxidation, and to improve the color stability and sensory properties of meat and meat products.

Research – Bacteria killed by new light-activated coating

Science Daily

To stop the spread of disease, it could be used to coat phone screens and keyboards, as well as the inside of catheters and breathing tubes, which are a major source of healthcare-associated infections (HCAIs).

The most well known HCAIs are caused by Clostridioides difficile (C. difficile), methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli). They commonly occur during in-patient medical or surgical treatment, or from visiting a healthcare setting and pose a serious health threat, making them a key priority for the NHS to address*.

The research, published today in Nature Communications, is the first to show a light activated antimicrobial coating successfully killing bacteria in low intensity, ambient light (300 Lux), such as that found in wards and waiting rooms. Previously, similar coatings needed intense light (3,000 Lux), like that found in operating theatres, to activate their killing properties.

The new bactericidal coating is made of tiny clusters of chemically modified gold embedded in a polymer with crystal violet — a dye with antibacterial and antifungal properties.

 

Research -Persistent contamination of Salmonella, Campylobacter, Escherichia coli, and Staphylococcus aureus at a broiler farm in New Zealand

Canadian Journal of Microbiology

Intensive poultry production due to public demand raises the risk of contamination, creating potential foodborne hazards to consumers. The prevalence and microbial load of the pathogens CampylobacterSalmonellaStaphylococcus aureus, and Escherichia coli was determined by standard methods at the farm level. After disinfection, swab samples collected from wall crevices, drinkers, and vents were heavily contaminated, as accumulated organic matter and dust likely protected the pathogens from the disinfectants used. The annex floor also showed high microbial concentrations, suggesting the introduction of pathogens from external environments, highlighting the importance of erecting hygiene barriers at the entrance of the main shed. Therefore, pathogen control measures and proper application of disinfectants are recommended as intervention strategies. Additionally, quantitative polymerase chain reaction (qPCR) was evaluated as a quantification tool. qPCR showed limitations with samples containing low microbial counts because of the low detection limit of the method. Thus, bacterial pre-enrichment of test samples may be necessary to improve the detection of pathogens by qPCR.

Research -An in situ-Synthesized Gene Chip for the Detection of Food-Borne Pathogens on Fresh-Cut Cantaloupe and Lettuce

Frontiers

Fresh foods are vulnerable to foodborne pathogens which cause foodborne illness and endanger people’s life and safety. The rapid detection of foodborne pathogens is crucial for food safety surveillance. An in situ-synthesized gene chip for the detection of foodborne pathogens on fresh-cut fruits and vegetables was developed. The target genes were identified and screened by comparing the specific sequences of Salmonella Typhimurium, Vibrio parahemolyticusStaphylococcus aureusListeria monocytogenes, and Escherichia coli O157:H7 from the National Center for Biotechnology Information database. Tiling array probes were designed to target selected genes in an optimized hybridization system. A total of 141 specific probes were selected from 3,227 hybridization probes, comprising 26 L. monocytogenes, 24 S. aureus, 25 E. coli O157:H7, 20 Salmonella Typhimurium, and 46 V. parahemolyticus probes that are unique to this study. The optimized assay had strong amplification signals and high accuracy. The detection limit for the five target pathogens on fresh-cut cantaloupe and lettuce was approximately 3 log cfu/g without culturing and with a detection time of 24 h. The detection technology established in this study can rapidly detect and monitor the foodborne pathogens on fresh-cut fruits and vegetables throughout the logistical distribution chain, i.e., processing, cleaning, fresh-cutting, packaging, storage, transport, and sale, and represents a valuable technology that support the safety of fresh agricultural products.

Research – VA/starch/propolis/anthocyanins rosemary extract composite films as active and intelligent food packaging materials

Wiley Online

Active and intelligent food packaging films has taken more importance over conventional packaging. The aim of this study was to develop active and intelligent food packaging films based on bio‐degradable polymers like polyvinyl alcohol and starch, incorporated with natural additives, that is, propolis extract (PE) and Anthocyanin. Boric acid was used as a cross‐linker. The results proved the compatibility of films mixture. The mechanical strength was also measured and highest value was achieved 6.1 MPa for films containing 20% PE. Moreover, the maximum zone of inhabitation, that is, 21 and 15 mm, was also achieved at same composition against Escherichia coli and methicillin‐resistant Staphylococcus aureus, respectively. Furthermore, all films had shown great color response against different pH ranging from 2 to 14. Finally, food spoilage test was performed using pasteurized milk. Films responded visibly by changing color and protected milk from spoilage. Hence, formulated bio‐degradable active and intelligent films can be used as food packaging material.

Research – Predicting the antimicrobial effect of probiotic lactic acid bacteria against Staphylococcus aureus in white cheeses, using Fourier series modeling method

Wiley Online

MRSA Staphylococcus KSW Food World

Image CDC

In this study, it was aimed to design the time‐predicted inactivation model for various growth curves and the growth parameters representing the changes in the inactivation of Staphylococcus aureus in probiotic white cheese. For this purpose, S. aureus were inoculated in the pasteurized milk and the production of probiotic white cheese was performed in five different groups, and then samples were matured for 60 days at 4°C. S. aureusLactobacillus rhamnosusLactobacillus casei Shirota, and mesophilic starter culture levels of the samples were analyzed on the 1st, 4th, 7th, 10th, 15th, 30th, and 60th days of maturation. The inactivation model evaluation was performed by using the number of microorganisms counted with Fourier modeling method. In determining the model to be applied, the coefficient of determination (R2) and the sum of squared errors (SSE) for the mean number of microorganisms detected via modeling method were used. As conclusions, the number of S. aureus has decreased by approximately 5 logarithmic units at the end of the storage period by using probiotics together with the starter culture. It was determined that the Fourier modeling method is a suitable inactivation model with R2 values of 0.9847–0.9986 and SSE values of 0.094–0.510.

Research – Indoor Particulate Matter From Smoker Homes Induces Bacterial Growth, Biofilm Formation, and Impairs Airway Antimicrobial Activity. A Pilot Study

Frontiers

Background: Particulate matter (PM) air pollution causes deleterious health effects; however, less is known about health effects of indoor air particulate matter (IAP).

Objective: To understand whether IAP influences distinct mechanisms in the development of respiratory tract infections, including bacterial growth, biofilm formation, and innate immunity. Additionally, we tested whether IAP from Iowa houses of subjects with and without recent respiratory exacerbations recapitulated the National Institute of Standards and Technology (NIST) IAP findings.

Methods: To test the effect of NIST and Iowa IAP on bacterial growth and biofilm formation, we assessed Staphylococcus aureus growth and Pseudomonas aeruginosa biofilm formation with and without the presence of IAP. To assess the effect of IAP on innate immunity, we exposed primary human airway surface liquid (ASL) to NIST, and Iowa IAP. Lastly, we tested whether specific metals may be responsible for effects on airway innate immunity.

Results: NIST and Iowa IAP significantly enhanced bacterial growth and biofilm formation. NIST IAP (whole particle and the soluble portion) impaired ASL antimicrobial activity. IAP from one Iowa home significantly impaired ASL antimicrobial activity (p < 0.05), and five other homes demonstrated a trend (p ≤ 0.18) of impaired ASL antimicrobial activity. IAP from homes of subjects with a recent history of respiratory exacerbation tended (p = 0.09) to impair ASL antimicrobial activity more than IAP from homes of those without a history respiratory exacerbation. Aluminum and Magnesium impaired ASL antimicrobial activity, while copper was bactericidal. Combining metals varied their effect on ASL antimicrobial activity.

Conclusions: NIST IAP and Iowa IAP enhanced bacterial growth and biofilm formation. ASL antimicrobial activity was impaired by NIST IAP, and Iowa house IAP from subjects with recent respiratory exacerbation tended to impair ASL antimicrobial activity. Individual metals may explain impaired ASL antimicrobial activity; however, antimicrobial activity in the presence of multiple metals warrants further study.