Category Archives: Staphylococcus aureus

Italy – Oligomineral Natural Mineral Water 1.5 lt – Staphylococcus aureus


Brand : Fonte Valle Reale

Name : Oligomineral Natural Mineral Water 1.5 lt

Reason for reporting : Recall due to microbiological risk

Publication date : 2 August 2022



Research – Terpenes Combinations Inhibit Biofilm Formation in Staphyloccocus aureus by Interfering with Initial Adhesion



The biofilm is a conglomerate of cells surrounded by an extracellular matrix, which contributes to the persistence of infections. The difficulty in removing the biofilm drives the research for new therapeutic options. In this work, the effect of terpenes (−)-trans-Caryophyllene, (S)-cis-Verbenol, (S)-(−)-Limonene, (R)-(+)-Limonene, and Linalool was evaluated, individually and in combinations on bacterial growth, by assay with resazurin; the formation of biofilm, by assay with violet crystal; and the expression of associated genes, by real-time PCR, in two clinical isolates of Staphyloccocus aureus, ST30-t019 and ST5-t311, responsible for more than 90% of pediatric infections by this pathogen in Paraguay. All combinations of terpenes can inhibit biofilm formation in more than 50% without affecting bacterial growth. The most effective combination was (−)-trans-Caryophyllene and Linalool at a 500 μg/mL concentration for each, with an inhibition percentage of 88%. This combination decreased the expression levels of the sdrD, spa, agr, and hld genes associated with the initial cell adhesion stage and quorum sensing. At the same time, it increased the expression levels of the cap5B and cap5C genes related to the production of capsular polysaccharides. The combinations of compounds tested are promising alternatives to inhibit biofilm formation in S. aureus. View Full-Text

France – Dry sausage 225g MN LR VPF – Staphylococcal Enterotoxins

Gov france

Identification information of the recalled product

  • Product category Feed
  • Product subcategory Meats
  • Product brand name Black Mountain
  • Model names or references Dry sausage 225g Montagne Noire Label Rouge VPF
  • Identification of products
    GTIN Batch Date
    3339720411429 D221726 Date of minimum durability 31/07/2022
    3339720411429 310618944 Date of minimum durability 08/26/2022
  • Packaging Microperforated bag
  • Marketing start/end date From 06/06/2022 to 06/07/2022
  • Storage temperature Product to be stored at room temperature
  • Health markFR.81.083.001 EC
  • Further information Batch and durability inscription on the bag
  • Geographic area of ​​sale Whole France
  • Distributors Carrefour – Galec – Intermarché – U system + various wholesalers and points of sale or factory outlets

Practical information regarding the recall

  • Reason for recall Presence of Staphylococcal enterotoxins
  • Risks incurred by the consumer Staphylococcus aureus (causative agent of staphylococcal poisoning)

Research – Effect of Biltong Dried Beef Processing on the Reduction of Listeria monocytogenes, E. coli O157:H7, and Staphylococcus aureus, and the Contribution of the Major Marinade Components


Biltong is a dry beef product that is manufactured without a heat lethality step, raising concerns of whether effective microbial pathogen reduction can occur during biltong processing. Raw beef inoculated with 4-strain cocktails of either E. coli O157:H7, Listeria monocytogenes, or Staphylococcus aureus, and processed with a standard biltong process, were shown to incur a >5-log reduction in 6–8 days after marination by vacuum-tumbling for 30 min in vinegar, salt, spices (coriander, pepper) when dried at 23.9 °C (75 °F) at 55% relative humidity (RH). Pathogenic challenge strains were acid-adapted in media containing 1% glucose to ensure that the process was sufficiently robust to inhibit acid tolerant strains. Internal water activity (Aw) reached < 0.85 at 5-log reduction levels, ensuring that conditions were lower than that which would support bacterial growth, or toxin production by S. aureus should it be internalized during vacuum tumbling. This was further confirmed by ELISA testing for staphylococcal enterotoxins A and B (SEA, SEB) after marination and again after 10 days of drying whereby levels were lower than initial post-marination levels. Comparison of log reduction curves obtained for E. coli O157:H7, L. monocytogenesS. aureus, and Salmonella (prior study) showed that microbial reduction was not significantly different (p < 0.05) demonstrating that even without a heat lethality step, the biltong process we examined produces a safe beef product according to USDA-FSIS guidelines.

Research – Sink survey to investigate multidrug resistance pattern of common foodborne bacteria from wholesale chicken markets in Dhaka city of Bangladesh

Antimicrobial resistance (AMR) among foodborne bacteria is a well-known public health problem. A sink survey was conducted to determine the AMR pattern of common foodborne bacteria in cloacal swab of broiler chickens and sewage samples from five wholesale chicken markets of Dhaka city in Bangladesh. Bacteria were identified by culture-based and molecular methods, and subjected to antimicrobial susceptibility testing. Resistance genes were identified by multiplex PCR and sequencing. Multidrug resistance (MDR) was observed in 93.2% of E. coli, 100% of Salmonella spp., and 97.2% of S. aureus from cloacal swab samples. For sewage samples, 80% of E. coli, and 100% of Salmonella and S. aureus showed MDR. Noteworthy, 8.3% of S. aureus from cloacal swab samples showed possible extensively drug resistance. Antimicrobial resistance genes (beta-lactamase—blaTEM, blaSHV; quinolone resistance gene—qnrS) were detected in a number of E. coli and Salmonella isolates from cloacal swab and sewage samples. The methicillin resistance gene (mecA) was detected in 47.2% and 25% S. aureus from cloacal swab and sewage samples, respectively. The findings envisage the potential public health risk and environmental health hazard through spillover of common foodborne MDR bacteria.

Research – Decontamination of Pathogenic and Spoilage Bacteria on Pork and Chicken Meat by Liquid Plasma Immersion


In this research, we aimed to reduce the bacterial loads of Salmonella Enteritidis, Salmonella Typhimurium, Escherichia coliCampylobacter jejuniStaphylococcus aureus, and Pseudomonas aeruginosa in pork and chicken meat with skin by applying cold plasma in a liquid state or liquid plasma. The results showed reductions in S. Enteritidis, S. Typhimurium, E. coli, and C. jejuni on the surface of pork and chicken meat after 15 min of liquid plasma treatment on days 0, 3, 7, and 10. However, the efficacy of the reduction in S. aureus was lower after day 3 of the experiment. Moreover, P. aeruginosa could not be inactivated under the same experimental conditions. The microbial decontamination with liquid plasma did not significantly reduce the microbial load, except for C. jejuni, compared with water immersion. When compared with a control group, the pH value and water activity of pork and chicken samples treated with liquid plasma were significantly different (p ≤ 0.05), with a downward trend that was similar to those of the control and water groups. Moreover, the redness (a*) and yellowness (b*) values (CIELAB) of the meat decreased. Although the liquid plasma group resulted in an increase in the lightness (L*) values of the pork samples, these values did not significantly change in the chicken samples. This study demonstrated the efficacy of liquid plasma at reducing S. Enteritidis, S. Typhimurium, E. coliC. jejuni, and S. aureus on the surface of pork and chicken meat during three days of storage at 4–6 °C with minimal undesirable meat characteristics. View Full-Text

Research – Microbiological Profile, Prevalence and Characterization of Salmonella enterica in Peanuts, Pecans, Raisins, Sun-dried Tomatoes, and Chocolate Sprinkles Sold in Bulk in Markets of Queretaro, Mexico 

Journal of Food Protection

In Mexico, the prevalence of Salmonella enterica in low water activity foods and their link to outbreaks is unknown. The aim of this study was to determine the microbiological profile and the prevalence of S. enterica in low water activity foods (peanuts, pecans, raisins, sun-dried tomatoes, and chocolate sprinkles) purchased in retail establishments in Queretaro, Mexico. Seventy samples of each food item sold in bulk were purchased. Aerobic plate count (APC), molds, yeasts, total coliforms, Escherichia coli, and Staphylococcus aureus were quantified in 10-g samples. The prevalence of S. enterica in 25 g samples was determined. From positive samples, S. enterica  isolates (60) were characterized based on their antimicrobial susceptibility to 14 antibiotics, the presence/absence of 13 virulence genes and serotype. The concentration of APC, molds, yeast, total coliforms, and E. coli ranged from 3.1-5.2 Log CFU g-1, 2.0-2.4 Log CFU g-1, 2.0-3.0 Log CFU g-1, 0.6-1.1 Log MPN g -1, and 0.5-0.9 Log MPN g -1, respectively. S. aureus  was not detected in any sample (<10 CFU g -1). The prevalence of  S. enterica in chocolate sprinkles, raisins, peanuts, pecans, and sun-dried tomatoes was 26%, 29%, 31%, 40%, and 52%, respectively. Most isolates (68.3%) were resistant to at least one antibiotic. The chromosome-associated virulence genes were found in all isolates and only one strain had sopE, and 98.3% of the isolates were grouped in the same virulotype. Among the isolates, the most frequent serotype was Tennessee (51/60). According to the characteristics evaluated, the isolates were grouped in 24 clusters. The elevated prevalence of S. enterica highlight the role of low water activity food items sold in bulk at markets as a potential vehicle for pathogens transmission. Regardless of the low variability among S. enterica isolates, their characterization could be helpful to elucidate which strains are circulating in these foods for improving epidemiological surveillance.

Research – PDIA, an Iminosugar Compound with a Wide Biofilm Inhibitory Spectrum Covering Both Gram-Positive and Gram-Negative Human Bacterial Pathogens


Many difficult-to-treat human infections related to catheters and other indwelling devices are caused by bacteria residing in biofilms. One of the key properties of microorganisms residing in a biofilm is decreased susceptibility towards antimicrobial agents. Therefore, many different approaches have been researched to destroy or inhibit biofilm production by bacteria. Different iminosugars (IS) were reported to inhibit biofilm formation in S. mutansS. aureus, and P. aeruginosa. The aim of this study was to look for a spectrum of the activity in one of these IS. The iminosugar PDIA beta-1-C-propyl-1,4-dideoxy-1,4-imino-L-arabinitol was tested in vitro at the same concentration against 30 different strains of the most important Gram-negative and Gram-positive human pathogens looking for their biofilm production and viability at different time intervals. It appeared that PDIA inhibited biofilm production of Enterobacter spp., P. aeruginosaEnterococcus spp. and S. aureus in 8 h, and Klebsiella spp., Acinetobacter spp. and S.epidermidis in 24 h. PDIA caused no growth inhibition of the tested bacteria at a concentration of 0.9 mM. Our results indicate a broad-spectrum biofilm inhibitory activity of PDIA. which may be the basis for future application studies that will help in control of the associated device and biofilm-related infections caused by a wide spectrum of the causative agents. View Full-Text

Research – New Challenges for Detection and Control of Foodborne Pathogens: From Tools to People


Contamination of foods by human pathogenic microorganisms is a major concern to both food safety and public health. The changes in consumers’ demand, the globalization of the food trade, and the progress on food production practices and processing technologies all pose new challenges for food industries and regulatory agencies to ensure the safety in food products.
With regard to microbiological safety, bacteria and viruses are the most common foodborne pathogens associated with both sporadic cases and outbreaks.
However, bacterial and viral microorganisms differ in terms of their behaviour in food matrices, their stability in food-related environments (e.g., food-contact surfaces, irrigating and processing waters), and their response to food processing technologies and controlling measures. Current methods do not meet all relevant criteria for effective monitoring plans, the main limitations being their sensitivity, the high workload and time requirement, and the inability to differentiate between viable and non-viable microorganisms. Thus, specific and sensitive methods need to be developed for their detection and quantification in com-plex matrices, such as food, for tracking their occurrence along the food chain to determine the sources of contamination, and for ultimately estimating the risk for consumers.
To fill these gaps, this Special Issue comprises four original research articles and are view paper focusing on the implementation of novel analytical techniques and approaches to foodborne pathogens along the food chain.
Zand and colleagues [1] reviewed the most recent advances of the application of flowcytometry (FCM) and fluorescence in situ hybridization (FISH) for the rapid detection and characterization of microbial contamination. FCM allows for a culture-independent quantification of microbial cells, also providing information on their physiological and structural characteristics which are relevant to assess their viability status. FISH is a nucleic acid-based method mainly applied in the medical and diagnostic fields. While FCM has been successfully used to detect and monitor microorganisms in water, state-of-the-art FCM and FISH protocols for food matrices still show significant limitations. The main pitfalls include complex sample preparation steps; the use of toxic substances; their limits of detection, especially for FISH assays; and the equipment price. Because of all these aspects, FCM and FISH have not yet gained considerable interest in food safety area for the detection of microbial pathogens. Future studies should focus on potential optimisation strategies for FCM and FISH protocols in food samples and their validation, as well as on the development of automated lab-on-chip solutions.
Moving to explore next-generation sequencing (NGS) applications in the produce industry, Truchado et al. [2] contributed to identify potential contamination niches of Listeria monocytogenes in a frozen vegetable processing plant. NGS is a sequencing technology that offers ultra-high throughput, a scalable and fast technique that allows the authors to characterize the isolates by a whole-genome sequencing (WGS) of 3multi locus sequence typing (MLST). The WGS analysis revealed the presence of four different sequence types (ST) contaminating 18% of the samples, including food contact surfaces (FCS), non-food contact surfaces (n-FCS), and final product. These ST were further classified into four different virulence types (VT) according to multi-virulence locus sequence typing (MVLST). Interestingly, an isolate detected in non-food-contact surfaces(n-FCS) also contaminated the final product, highlighting the relevant role of n-FCS as reservoir of L.monocytogenes that reached the final product.
Staphylococcus aureus is a foodborne pathogen considered to be one of the etiological agents of food-related disease outbreaks. Leng et al. [3] supported this Special Issue with a study on its control using the skin mucus extract of Channa argus as a source of antimicrobial compounds. Of interest, untargeted metabolomics were applied to decipherits antibacterial mechanism against S. aureus. Results indicated that the extract had great inhibitory action on its growth by inducing the tricarboxylic acid cycle and amino acid biosynthesis, which are the primary metabolic pathways that affect the normal physiological functions of biofilms.
The present collection includes a second contribution on the control of S. aureus authored by Kim and colleagues [4] who developed a real-time PCR method (qPCR) for the rapid detection and quantification of pathogenic Staphylococcus species.
Four specific molecular targets were identified based on pan-genome analysis, and results showed 100% specificity for 100 non-target reference strains with a detection limit as low as 102CFU/mL. Thus, the proposed method allows an accurate and rapid monitoring of Staphylococcus species and may help control staphylococcal contamination of food.
Moving to human viral pathogens, Macaluso et al. [5] reported the results of an investigation aimed to characterize the occurrence of human enteric viruses in shellfish, a food item with relevant risk for consumers. The study included data collected over two years on the prevalence of enteric virus contamination along the shellfish production and distribution chain in Sicily, Italy. The findings based on quantitative reverse transcription polymerase chain reactions (RT-qPCRs), as gold-standard molecular technique, showed that almost 6% of samples were contaminated with at least one enteric virus such as norovirus, hepatitis A virus, and/or hepatitis E virus. The origin of contaminated shellfish was traced back to Spain and several municipalities in Italy. Such contribution highlights the relevance
of routine monitoring programs to prevent foodborne transmission of enteric viruses and
preserve the health of consumers.
In summary, this Special Issue compile several contributions focused on novel technologies, approaches, and strategies demonstrated to be effective in controlling microbial contamination in food. All the articles provide valuable information to monitor and/or reduce contamination in food, food industry settings, and along the food chain. On a final note, the collection emphasizes the relevance of ensuring food safety and limiting the risk of microbiological contamination along the food chain to protect consumers.

Research – The Response and Survival Mechanisms of Staphylococcus aureus under High Salinity Stress in Salted Foods


Staphylococcus aureus (S. aureus) has a strong tolerance to high salt stress. It is a major reason as to why the contamination of S. aureus in salted food cannot be eradicated. To elucidate its response and survival mechanisms, changes in the morphology, biofilm formation, virulence, transcriptome, and metabolome of S. aureus were investigated. IsaA positively regulates and participates in the formation of biofilm. Virulence was downregulated to reduce the depletion of nonessential cellular functions. Inositol phosphate metabolism was downregulated to reduce the conversion of functional molecules. The MtsABC transport system was downregulated to reduce ion transport and signaling. Aminoacyl-tRNA biosynthesis was upregulated to improve cellular homeostasis. The betaine biosynthesis pathway was upregulated to protect the active structure of proteins and nucleic acids. Within a 10% NaCl concentration, the L-proline content was upregulated to increase osmotic stability. In addition, 20 hub genes were identified through an interaction analysis. The findings provide theoretical support for the prevention and control of salt-tolerant bacteria in salted foods. View Full-Text