Category Archives: Staphylococcus aureus

Research – An approach to improve the safety and quality of ready‐to‐eat blueberries

Wiley Online

Abstract

Bioactive edible coatings were developed and applied to blueberries as a natural treatment. E. coli O157:H7, L. innocuaS. aureus, and P. aeruginosa were subjected to four bioactive compounds and to three film‐forming solutions (FFS). Vanillin and geraniol at low concentrations (1.2–1.8 mg/mL and 0.4–1 μL/mL) demonstrated significant inhibitory effects on all pathogens counts. Chitosan (Ch) showed a high antimicrobial activity (final counts below 2 log CFU/mL). The effectiveness of Ch plus vanillin (Ch‐Va) and geraniol (Ch‐Ge) in improving the safety were tested against pathogens inoculated on blueberries. Ch, Ch‐Va, and Ch‐Ge coatings exerted a bactericidal effect on all pathogens (from 1.24 to more than 2 log reductions). Significant reduction in yeast and mold counts was achieved with Ch (1.09 log) and Ch + Va (1.74 log). Sensory attributes of blueberries remained acceptable. Ch‐Va and Ch‐Ge were an alternative to improve the quality and safety and could be effective in extending the shelf life of ready‐to‐eat blueberries.

Practical applications

The present study proposes the use of natural coatings enriched with biopreservatives as a technological alternative to enhance the quality and safety of minimally processed fruits. According to the results obtained, the application of chitosan plus vanillin/geraniol coatings on fresh blueberries would allow to offer a safe product and respond the growing demand of consumers for fresh, environmentally friendly and chemical preservatives‐free foods. These findings and those obtained by the sensory evaluation support the practical application of this alternative in the minimally processed fruit industry.

Research – Inactivation of Staphylococcus aureus and Escherichia coli in milk by different processing sequences of ultrasound and heat

Wiley Online

Abstract

Different processing sequences of ultrasound and heat were applied for the inactivation of Staphylococcus aureus and Escherichia coli in milk. The changes in whey protein content, particle size, zeta potential, pH, viscosity, and color values were studied to evaluate the effects on the quality of milk. Results indicated ultrasound treatment (600 W, 5 min) with postheating (63 °C 5 min) reduced S. aureus and E. coli by 1.58 and 2.02 log cfu/ml, respectively, but yielded 0.26 and 0.19 log cfu/ml sublethal S. aureus and E. coli. Milk preheated to 63 °C (5 min) followed by ultrasound (600 W, 5 min) showed 1.17 and 1.68 log reductions for S. aureus and E. coli, respectively, and the sublethal S. aureus and E. coliwere reduced to 0.16 and 0.09 log cfu/ml. The increased cavitation effects make the simultaneous treatment (600 W, 63 °C, 5 min) the most effective approach in killing S. aureus and E. coli, causing 1.67 and 2.16 log reductions, respectively, and producing negligible sublethal bacteria. The simultaneous treatment was also able to improve some physical–chemical properties of milk; smaller particle size and whiter color were achieved. However, whey protein and stability indices of milk were slightly deteriorated by this approach.

Practical applications

In food processing fields, thermosonication can serve as an alternative processing technique to thermal pasteurization. Especially, the simultaneous treatment of ultrasound and heat showed best inactivation effect for viable and sublethal cells, while maintaining the overall milk quality in the meantime. The results of this research may be useful for the treatment of various bacterial contamination and give the guidance for milk processing

Research – Microbial risks in food franchise: A step forward in establishing ideal cleaning and disinfection practices in SSOPs

Wiley Online

Abstract

Microbial contamination in coffee specialty franchises using uniform processing procedures in Korea was examined. Cleaning or disinfection practices for sanitation standard operating procedures (SSOPs) are proposed. For each processing step, food materials and associated processing environments were tested for heterotrophic bacteria (HB), Escherichia coli, coliform, and Staphylococcus aureus. Existing SSOP cleaning or disinfection practices were also evaluated. Ice‐making procedures revealed coliform and HB contamination in all coffee houses, with high HB contamination on several supplementary food materials and associated food utensils. Microbial loads in food materials or final products were high on structures and materials that are difficult to clean and disinfect. Staphylococcus species contaminated food machinery and utensils directly contacted by food handlers. Based on our analysis of cleaning and disinfection practices in each franchise’s SSOPs, current practices should be complemented to ensure food safety. Our results provide a foundation for developing sanitation standards optimized for coffee specialty franchises.

Practical applications

Franchise brands operating collectively require well‐established sanitation practices such as sanitation standard operating procedures (SSOPs) to ensure food safety and quality. Microbiological studies were performed to evaluate coffee processing procedures and environments at specialty franchise brands. Hygiene practices in SSOPs were simultaneously evaluated to examine cleaning and disinfection procedures. In several processing procedures and associated processing environments, coliform and Staphylococcus aureus were detected on food handlers’ hands, gloves, and hand‐accessible areas of food utensils or machinery simultaneously. Coliforms were also detected in edible ice cubes and on related utensils or machinery for ice production or storage (ice‐making machine, ice‐bin). Heterotrophic bacteria (HB) were detected at high densities in sugar syrup (under‐using) and edible ice (during production and storage). Particularly, HB concentrations increased during processing. Thus, microbial contamination is increased by various factors during processing, particularly inappropriate cleaning or disinfection of utensils or machinery. Evaluation of cleaning and disinfection practices for each franchise’s SSOPs revealed that the cleaning and disinfection practices for machinery or utensils accessible to worker’s hands must be supplemented. Establishments serving a wide variety of coffee beverages may require complex and different processing procedures. Because utensils and machinery affecting the microbial load of the final product can vary, the areas and targets of cleaning and disinfection should be expanded. Second, the structure or material characteristics of food utensils or machinery that are difficult to clean and disinfect can lead to microbial growth. Cleaning or disinfection of food utensils or machinery should be considered in SSOPs. Purchasing management (as a major category of SSOPs for food safety) should be expanded to utensils or machinery in addition to food materials. Furthermore, cleaning and disinfection targets aimed at under‐used utensils or facilities must be established in SSOPs.

Research – Detection of pathogenic bacteria and fungi on biometric surface of Automated Teller Machines located in Brazilian public hospital

Academic Journals

The Automated Teller Machine (ATM) is used by millions of people as an alternative to gain time instead of using traditional banking systems in Brazil and ATMs are frequently localized in São Paulo city around the hospitals. However, ATMs might be potential devices for microbial accumulation and transmission in the community. The objective of the present study was to evaluate forty-two ATMs, in two hospital areas (A and B) in São Paulo city for the presence of pathogenic fungi and bacteria. Samples were collected from biometric surfaces of the devices with sterile cotton swabs soaked in the sterile physiologic saline and were cultured on selective agar for yeasts, filamentous fungi and bacteria in the period of January 2017 to March 2018. Complementary biochemical tests were applied to confirm the bacteria and the taxonomic identification of molds was performed considering the morphological characteristics by microscopic observation. Our results suggest that the biometric surfaces in ATMs is an important environmental source of microbes, once that the genera Staphylococcus was predominant in all agencies of both hospital areas (83.3%), following of Streptococcus spp. (57%) and Enterococcus spp. (50%). The group of Enterobacteriaceae (Gram negative bacilli) were most frequent in both areas studied (57%). Seven different fungi genera were isolated from ATMs in area A and B and yeasts were predominant in all samples collected (47%), comparing with filamentous fungi (23%). We conclude that biometric ATM surfaces play an important role in microbial transmission in hospital settings, and healthcare professionals should wash and disinfect their hands carefully before touching patients.

 

Research – Enzymatic Inactivation of Pathogenic and Nonpathogenic Bacteria in Biofilms in Combination with Chlorine

Journal of Food Protection

This study investigated the effects of enzyme application on biofilms of bacterial isolates from a cafeteria kitchen and foodborne pathogens and the susceptibility of Salmonella biofilms to proteinase K combined with chlorine treatment. For four isolates from a cafeteria kitchen (Acinetobacter, Enterobacter, and Kocuria) and six strains of foodborne pathogens (Salmonella enterica, Staphylococcus aureus, and Vibrio parahaemolyticus), the inhibitory effect of enzymes on biofilm formation at 25°C for 24 h or the degradative efficacy of enzymes on 24-h mature biofilm at 37°C for 1 h in tryptic soy broth (TSB) was examined in a polystyrene microtiter plate. The effect of enzymes was also evaluated on a subset of these strains in 20 times diluted TSB (1/20 TSB) at 25°C. The working concentrations of five enzymes were 1 U/100 μL for α-amylase, amyloglucosidase, cellulase, and DNase and 1 milli-Anson unit/100 μL for proteinase K. In addition, 24-h mature SalmonellaTyphimurium biofilm on a stainless steel coupon was treated with proteinase K for 1 h at 25°C followed by 20 ppm of chlorine for 1 min at 25°C. The results showed that certain enzymes inhibited biofilm formation by the kitchen-originated bacteria; however, the enzymatic effect was diminished on the mature biofilms. Biofilm formation of V. parahaemolyticus was suppressed by all tested enzymes, whereas the mature biofilm was degraded by α-amylase, DNase I, and proteinase K. Proteinase K was effective in controlling Salmonella biofilms, whereas a strain-dependent variation was observed in S. aureusbiofilms. In 1/20 TSB, Enterobacter cancerogenus and Kocuria varians were more susceptible to certain enzymes during biofilm formation than those in TSB, whereas the enzymatic effect was much decreased on 24-h mature biofilms, regardless of nutrient conditions. Furthermore, synergistic inactivation of Salmonella Typhimurium in biofilms was observed in the combined treatment of proteinase K followed by chlorine. Live/Dead assays also revealed a decrease in density and loss of membrane integrity in Salmonella Typhimurium biofilms exposed to the combined treatment. Therefore, certain enzymes can control biofilms of isolates residing in a cafeteria kitchen and foodborne pathogens. This study demonstrates the potential of enzymes for the sanitation of food processing environments and of proteinase K combined with chlorine to control Salmonella biofilms on food contact surfaces.

Research – Microbiological and chemical quality of ice used to preserve fish in Lisbon marketplaces

Wiley Online

Abstract

Ice is widely used to preserve fish on markets, playing a major role in the food industry. If manufactured, stored or distributed in inadequate sanitary conditions, it can represent a considerable health risk for both consumers and professionals. The present study characterizes ice used in marketplaces, on microbiological and chemical parameters. The aim was to assess potential risks on occupational exposure and consumer safety and therewith plan orientation guidelines. Sampling took place in 18 marketplaces in Lisbon, with ice samples collected at three different stages—production (n = 29), storage (n = 30), and product‐contact (n = 29). No significant contamination was found in production and storage stages, demonstrating that ice production and storage procedures are adequate regarding sanitary conditions. With exception for Salmonella, significantly higher concentrations of microbial parameters were identified in product‐contact stages, specifically Total Coliforms (548 MPN/100 mL), Escherichia coli (1 MPN/100 mL), Enterococci (29 MPN/100 mL), Staphylococcus aureus (271 CFU/100 mL), HPC at 5°, 22°, and 37° (>301 CFU/mL). Our study also shows that the majority of samples from ice production and storage comply with national regulations regarding drinking water quality. Yet, occupational health and consumer risks may still exist at the final product‐contact stage, as significant contamination was detected..

Practical applications

The present study can be used as a model for ice quality monitoring in fish preservation, serving as a tool for quality control and fast contamination detection during the several process stages.

This monitoring model is an important contribution for assuring the safety of the preserved products, as well as, occupational health improvement and consumer risk protection.

Information – CDC – Staph infections can kill

CDC

MRSA Staphylococcus KSW Food World

Image CDC

Overview

Staphylococcus aureus (staph) is a germ found on people’s skin. Staph can cause serious infections if it gets into the blood and can lead to sepsis or death.

  • Staph is either methicillin-resistant staph (MRSA) or methicillin-susceptible staph (MSSA).
  • Staph can spread in and between hospitals and other healthcare facilities, and in communities.
  • People are at higher risk for staph infection when they have surgery or stay in healthcare facilities, have medical devices in their body, inject drugs, or when they come in close contact with someone who has staph.
  • Additional tactics in healthcare—such as decolonization (reducing germs people may carry and spread) before surgery—along with current CDC recommendations could prevent more staph infections.