Research – Inhibition of Listeria monocytogenes growth on vacuum packaged rainbow trout (Oncorhynchus mykiss) with carvacrol and eugenol

Wiley Online Library

Abstract

The aim of this study was to evaluate the effects of carvacrol and eugenol, separately and in combination, on survival of Listeria monocytogenes, and sensory and microbiological characteristics in vacuum packaged Oncorhynchus mykiss during refrigerated storage (4 ± 1 °C) for 20 days. The control fish fillets were analyzed for microbial (total mesophilic and psychrotrophic bacteria and lactic acid bacteria) and sensory properties. Fish fillets treated with carvacrol, eugenol, and their combination displayed populations of L. monocytogenes significantly lower, by 1.35–2.84 log cfu/g, than the control fillets during the whole storage period. No significant differences between groups of fish fillets with different active compound(s) added were noted except at the end of the storage, when the number of L. monocytogenes was significantly lower in the fish fillets with eugenol added. Sensory analysis showed that fish fillets with eugenol added were the most acceptable to trained panelists.

Practical applications

Taking into account the increasing need for the production of safe fish and fish products and the fact that carvacrol and eugenol, which exhibited significant antilisterial effect, are generally recognized as safe they can find its practical application in fish industry. Furthermore, as these substances are major constituents of numerous essential oils they can be considered as natural preservatives and used in the organic production as a substitute with synthetic additives which can cause adverse effects.

Research – Prevalence, genotyping, serotyping, and antibiotic resistance of isolated Salmonella strains from industrial and local eggs in Iran

Wiley Online Library

Abstract

This present study aimed to evaluate prevalence and characterization of serotypes, antimicrobial resistance (AMR) and genotypic profiles of Salmonella isolates in industrial and local eggs from Zanjan province of Iran. A total of 120 egg samples were collected and processed according to bacteriological analytical manual to isolate Salmonella strains from both eggs surface and contents. PCR method and genotyping were used to verify, identification and classification of isolates by screening invA genes and 16 s‐rRNA gene sequencing. Salmonella contamination rate in eggshell and contents of industrial and local eggs were 0% and 1.66%, respectively. High degree of AMR was observed to nalidixic acid and erythromycin. Gene sequencing for each isolates showed more similarity with Salmonella enterica subsp. enterica serovar Enteritidis and Salmonella enterica subsp. enterica serovar Typhimurium strains.

Practical applications

Salmonella contamination in eggs and the role of healthy chickens as reservoir and distributer of Salmonella in poultry farms can be a common food safety concern for public health. Therefore, Continuous monitoring of presence Salmonella and their antimicrobial resistance is of critical importance. Present study gives an insight of the current statues of egg’s contamination with Salmonella isolates, their antimicrobial resistance, genotupic profile, and epidemiological relationship in Iran.

Research – Prevalence, antimicrobial susceptibility and virulence genes of Staphylococcus aureus isolated from pork meat in retail outlets in India

Wiley Online

Abstract

Isolation of Staphylococcus aureus was carried out in a total of 120 retail pork samples and the overall prevalence of S. aureus in retail pork meat was 76.67%. All the isolates were resistant to both Ampicillin and Tetracycline (100%) followed by Cefoxitin, Oxacillin, Erythromycin, Amoxicillin, and Novobiocin. The multiple antibiotic resistance index of majority of the isolates were 0.3 and above. Methicillin resistance based on polymerase chain reaction revealed that 76.09% carried either mecA or mecC. The prevalence of enterotoxigenic S. aureus in pork was 82.61% and of the various toxin genes sei was the major gene followed by segsebsej, sed, seh, sec, and sea in decreasing order. The prevalence of multidrug resistant and virulent S. aureus carrying enterotoxin genes in retail pork meat is a clear indication of the potential of these isolates in causing foodborne intoxication under favorable conditions to the consumers.

Practical application

Staphylococcus aureus (S. aureus) is a well‐known opportunistic pathogen widely present in a broad host range, including human beings and food producing animals, such as pigs, cows, goats and chickens. It has the potential to contaminate animal products and they gain entry in to the food chain, during processing, preparation and storage. The wide use of antibiotics has led to the emergence of multi drug resistant strains, particularly Methicillin‐resistant S. aureus (MRSA). The present study highlights the prevalence, antimicrobial resistance with special reference to MRSA and enterotoxin gene profile of S. aureus isolated from retail pork meat. The results will provide the insights of the existing situation of antimicrobial resistance in pork meat in India.

Research – Evaluation of the effects of temperature on processed coffee beans in the presence of fungi and ochratoxin A

Wiley Online

Abstract

The coffee bean is sensitive to contamination with ocratoxigenic fungi; temperature influences the growth, and germination of these fungi, as well as the fungal toxins produced. The objectives of this study were to assess the distribution of toxigenic species, analyze the concentration of ochratoxin A (OTA) in Arabica coffee beans, and aplicate a mathematical model that considers the influence of actual temperature to predict the effects of projected temperature increase on OTA production. This toxin was, however, not detected in any of the coffee bean species analyzed here. The species with the highest incidence were Aspergillus niger and Aspergillus ochraceus. The results of the mathematical model demonstrated the influence of temperature on the production of the toxin. This information indicates the distribution of toxigenic fungal species in the regions of coffee cultivation in Minas Gerais, and thus, will assist the producers in adopting preventive measures.

Practical applications

Brazil is the largest coffee producer and exporter, which makes it a leader in the global coffee market; the state of Minas Gerais is responsible for 50% of this production. Following the global trend, Brazil has regulated the maximum permissible limit for ochratoxin A in coffee beans. This has led to a great interest in monitoring fungi and toxin production, mainly during the postharvest stage in the coffee cultivation regions of Brazil. Preventive measures can aid in the safe production of coffee beans, and the use of mathematical models capable of predicting the growth and production of fungal toxins are fundamental to informing the producers of the most favorable conditions in terms of temperature, as well as increases in ambient temperature, in specific regions of interest

Research – Prevalence of Shiga‐like toxin producing Escherichia coli strain (E. coli O157) in freshly consumed vegetables and its characterization

Wiley Online Library

Abstract

Escherichia coli is a vast genus with various beneficial to harmful species. O157:H7 is a shiga‐like toxin (stx) producing E. coli that cause’s major health threats in humans, through oral route. However, the presence of E. coli O157:H7 in vegetables is not yet reported in India. Hence, we surveyed the vegetables markets and enumerated the presence of E. coli O157 in freshly consumed vegetables namely, cucumber, radish, lettuce, cabbage, and menthos. Three consecutive surveys from three different market areas were done with 1 month interval. A total of 603 E. coli colonies were isolated. Presence of shiga toxin genes (Stx) were confirmed by colony polymerase chain reaction (PCR) using Stx1 and Stx2 markers that showed 25 and 12 positive colonies, respectively. Among the five vegetables, cabbage had the highest Stx positive colonies (16%). Compared to supermarkets, vegetables from the farmers market did not have much load of E. coli O157. Further, characterization of isolated E. coli colonies were performed using PCR techniques with gene specific markers namely, E. coli uidA, E. coli O157 specific uidA and intimin gene markers. Our analysis showed 6% of E. coli O157 population in the freshly consumed vegetables much above than 2% threshold level, thus providing a warning foresight related to disease outbreak.

Practical applications

Molecular survey using a number of Escherichia coli O157 specific genes through PCR is an easy, rapid, and a reliable method for pathogenic bacteria identification and characterization amidst other indigenous microbial load. Additionally, polymerase chain reaction (PCR)‐based enumeration of E. coli O157 in vegetables assist us in determining the threshold level for forewarning of pathogenic disease outbreaks. Further, the severity of outbreak could be predicted using E. coli O157 specific shiga toxin (stx) and receptor genes (intimin). The presence of E. coli O157 specific shiga toxins and intimins in a pathogen signifies severity and virulence of strains in causing potential outbreaks. PCR‐based studies enables rapid identification of inoculums source (E. coli O157 spread) from farmers field/cattle shed. Thus, it could be reliably used to stop the further spread of disease from the source inoculums during the outbreaks.

USA – FDA Report on E. Coli O157 Outbreak in Romaine Lettuce Points to “Significant” Finding of Strain in Sediment of Water Reservoir

Food Safety Tech 

The November 2018 outbreak of E.coli O157:H7 infections linked to romaine lettuce caused 62 illnesses across 16 states. The FDA zeroed in on the Central Coast growing regions of northern and Central California as being responsible for the contamination. The outbreak was declared over on January 9 and yesterday FDA released the report, “Factors Potentially Contributing to the Contamination of Romaine Lettuce Implicated in the Fall 2018 Multi-State Outbreak of E.Coli O157:H7”, which provides an overview of the investigation.

The report states that a sediment sample coming from an on-farm water reservoir in Santa Maria (Santa Barbara County, California) tested positive for the outbreak strain of E. coli O157:H7. Although this particular farm was identified in several legs of the Fall 2018 traceback investigations that occurred in the United States and Canada, as well as being a possible supplier of romaine lettuce in the 2017 traceback investigations, the FDA said that the farm is not the single source of the outbreak, as there is “insufficient evidence”. The traceback suggests that the contaminated lettuce could have come from several farms, because not all tracebacks led to the farm on which the contaminated sediment was found.

 

RASFF Alert – Aflatoxin – Hazelnuts – Blanched Groundnuts – Groundnuts – Pistachios – Organic Muesli

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RASFF – aflatoxins (B1 = 21; Tot. = 22 µg/kg – ppb) in hazelnuts from Turkey in the Netherlands

RASFF – aflatoxins (B1 = 6.7; Tot. = 7.7 µg/kg – ppb) in blanched groundnuts from the United States in the Netherlands

RASFF – aflatoxins (B1 = 23; Tot. = 26 µg/kg – ppb) in blanched groundnuts from Argentina in the Netherlands

RASFF – aflatoxins (B1 = 10; Tot. = 15 µg/kg – ppb) in groundnut kernels from Argentina in the Netherlands

RASFF – aflatoxins (B1 = 33.5; Tot. = 36.9 µg/kg – ppb) in groundnuts in shell from Egypt in Italy

RASFF – aflatoxins (B1 = 11; Tot. = 13 µg/kg – ppb) in groundnuts from Paraguay in the Netherlands

RASFF – aflatoxins (B1 = 2.7 µg/kg – ppb) in groundnuts from Argentina in the Netherlands

RASFF – aflatoxins (B1 = 16.93; Tot. = 19.09 µg/kg – ppb) in roasted and salted pistachios in shell from Turkey in Germany

RASFF – aflatoxins (B1 = 2.2 µg/kg – ppb) in groundnuts from Argentina in the Netherlands

RASFF – aflatoxins (B1 = 18; Tot. = 60 µg/kg – ppb) in groundnuts from Argentina in the Netherlands

RASFF – aflatoxins (B1 = 4.9; Tot. = 5.6 µg/kg – ppb) in blanched groundnuts from the United States in the Netherlands

RASFF – aflatoxins (B1 = 7.6 µg/kg – ppb) in blanched groundnuts from the United States in the Netherlands

RASFF – aflatoxins (B1 = 36; Tot. = 40 µg/kg – ppb) in blanched groundnuts from the United States in the Netherlands

RASFF – aflatoxins (B1 = 5.7; Tot. = 8.8 µg/kg – ppb) in organic muesli from Belgium in Belgium

RASFF – aflatoxins (B1 = 46.87; Tot. = 56.11 µg/kg – ppb) in pistachio nuts without shell from Iran, via Turkey in Italy