Editorial - Food Microbiology 2020

Food microbiology studies the microbiota of food products

Antibiotic Resistance and Virulence Factors among Enterococci Isolated from Chourico, a Traditional Portuguese Dry Fermented Sausage

Enterococci are ubiquitous microorganisms, found as part of the normal intestinal microbiota of many animals. They can be present in food products, for example, the Portuguese dry fermented sausage chourico. Twenty enterococci were isolated from chourico in two processing units; after identification and typification by conventional-molecular methods, the isolates were screened for virulence factors and antibiotic resistance. Identification allocated all enterococci to the species Enterococcus faecalis, and PCR fingerprinting demonstrated that each isolate was specific to the processing unit and chourico from which it was recovered. Regarding the screening for virulence factors, I strain produced cytolysin and 4 were gelatinase positive, but none produced lipase. The ace gene was detected in I enterococci, ebpABC and efaA(fs). in 16 isolates each, esp in 3, fsrB in 5, gelE in 7, and cylA in I. A multiresistant phenotype was observed in 8 isolates, 6 belonging to factory A. The antibiotic resistance gene ere(B) was detected in 9 enterococci, whereas the genes tet(M), aac(6')-le-aph(2 ''), and vanA were detected in 8 isolates each. As some of the E. faecalis chourico isolates present a multiresistant profile and harbor virulence and/or resistance genes, to assess further the safety of Portuguese dry sausages, a larger number of products and processing units must by analyzed

Salmonella sp. in edible offal (liver and tongue) from pigs slaughtered for consumption

During this study, 120 samples from slaughtered pigs (tongue swabs, n=40; liver swabs, n=40; liver parenchyma, n=40) were collected in a slaughterhouse. Salmonella sp. was isolated using conventional microbiological methods and strains were analyzed using serotyping, antimicrobial susceptibility testing and macrorestriction profiling (MRP) by Pulse Field Gel Electrophoresis (PFGE), to identify clonal relationships and potential contamination sources

Molecular Typing, Virulence Traits and Antimicrobial Resistance of Diabetic Foot Staphylococci

Diabetes mellitus is a major chronic disease that continues to increase significantly. One of the most important and costly complications of diabetes are foot infections that may be colonized by pathogenic and antimicrobial resistant bacteria, harboring several virulence factors, that could impair its successful treatment. Staphylococcus aureus is one of the most prevalent isolate in diabetic foot infections, together with aerobes and anaerobes

Food Microbiology- Editorial

Food microbiology comprehends the study of microorganisms that colonise, modify, and process, or contaminate and spoil food. It is one of the most diverse research areas within microbiology. It comprises a wide variety of microorganisms including spoilage, probiotic, fermentative, and pathogenic bacteria, moulds, yeasts, viruses, prions, and parasites. It deals with foods and beverages of diverse composition, combining a broad spectrum of environmental factors, which may infuence microbial survival and growth. Food microbiology includes microorganisms that have benefcial or deleterious efects on food quality and safety and may therefore be of concern to public health. Among the 39 submitted manuscripts, 22 have been selected to be part of this special issue on food microbiology in a broad sense

Salmonella sp. in edible offal (liver and tongue) from pigs slaughtered for consumption

During this study, 120 samples from slaughtered pigs (tongue swabs, n=40; liver swabs, n=40; liver parenchyma, n=40) were collected in a slaughterhouse. Salmonella sp. was isolated using conventional microbiological methods and strains were analyzed using serotyping, antimicrobial susceptibility testing and macrorestriction profiling (MRP) by Pulse Field Gel Electrophoresis (PFGE), to identify clonal relationships and potential contamination sources.</p

Selection of staphylococci strains isolated from a Portuguese traditional fermented/dry sausage for potential use as starter cultures Selection of staphylococci strains isolated from a Portuguese traditional fermented/dry sausage for potential use as star

To cite th is article / Pou r citer cet article -------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Abstract. In order to evaluate its potential use as starter cultures, 104 isolates of Staphylococcus spp. were obtained from sausages and different sampling environment points in workshops A and B, at southern region of Portugal. PCR amplification was carried out to confirm genus and species allocation. From workshop A, 47 isolates were staphylococci, the majority belonging to the specie S. equorum, while from workshop B, of the 57 isolates identified as staphylococci, most were S. xilosus. The genetic profiles of isolates were further compared using PCR fingerprinting analysis, guiding to the selection of 43 representative strains subsequently characterized for their nitrate reductase, lipolytic and proteolytic activities. Among these strains, 30% revealed proteolytic ability while 42% had lipolytic activity. 65% of the strains reduced nitrate. Subsequently, 10 strains (representatives of different fingerprinting groups) were evaluated for their ability to grow at different temperatures, pH and NaCl concentrations. S. xylosus and S. equorum showed to growth under all the studied conditions being more effective at 15°C, 20°C and pH 5.5 at 20°C, and NaCl concentrations of 10% and 15%; therefore can be guaranteed their application in technological processes with varying temperatures. In workshop A, strains P05-58 S. carnosus and P05-74 S. equorum and, from workshop B, P06-01 and P06-26 S. xylosus presented the most interesting features. Keywords. Staphylococcus coagulase negative -Fermented meat products -Starter culture -Proteolytic activity -Lipolytic activity -Nitrate reductase activity. Sélection de souches de staphylocoques isolées à partir de produits carnés traditionnels portugai

Selection of staphylococci strains isolated from a Portuguese traditional fermented/dry sausage for potential use as starter cultures

In order to evaluate its potential use as starter cultures, 104 isolates of Staphylococcus spp. were obtained from sausages and different sampling environment points in workshops A and B, at southern region of Portugal. PCR amplification was carried out to confirm genus and species allocation. From workshop A, 47 isolates were staphylococci, the majority belonging to the specie S. equorum, while from workshop B, of the 57 isolates identified as staphylococci, most were S. xilosus. The genetic profiles of isolates were further compared using PCR fingerprinting analysis, guiding to the selection of 43 representative strains subsequently characterized for their nitrate reductase, lipolytic and proteolytic activities. Among these strains, 30% revealed proteolytic ability while 42% had lipolytic activity. 65% of the strains reduced nitrate. Subsequently, 10 strains (representatives of different fingerprinting groups) were evaluated for their ability to grow at different temperatures, pH and NaCl concentrations. S. xylosus and S. equorum showed to growth under all the studied conditions being more effective at 15° C, 20° C and pH 5.5 at 20° C, and NaCl concentrations of 10% and 15%; therefore can be guaranteed their application in technological processes with varying temperatures. In workshop A, strains P05-58 S. carnosus and P05-74 S. equorum and, from workshop B, P06-01 and P06-26 S. xylosus presented the most interesting features

What is the main processing factor influencing Staphylococcus species diversity in different manufacturing units?

The microbiota of traditional dry-cured sausages and industrial environment was assessed to characterize the diversity of coagulase-negative staphylococci (CNS), and establish potential relationships with hygiene level or technological characteristics. Eight processing units from South Portugal were audited according to a checklist of requirements. Environmental and products’ samples at different production stages were evaluated regarding hygiene and safety criteria. CNS were recovered, characterized, and their potential use as starters evaluated. Low genetic diversity was observed for Staphylococcus xylosus, whereas Staphylococcus equorum showed diverse genetic profiles. Staphylococcus xylosus predominated in products with a long period of cold smoking, Staphylococcus saprophyticus in products with a long period of hot smoking, Staphylococcus epidermidis in products with a short period of cold smoking, and S. equorum in nonsmoked products. Most S. xylosus were resistant to tetracycline, whereas S. equorum were susceptible. Antibioresistance restricted the selection of starters due to safety recommendation