Effect of Chitosan and Alginate-Based Edible Membranes with Oregano Essential Oil and Olive Oil in the Microbiological, Physicochemical and Organoleptic Characteristics of Mutton

Edible chitosan or alginate coatings and their combinations with oregano essential oil or olive oil, have been examined for their effect on the microbiological, physicochemical and organoleptic characteristics of mutton. The results indicated that these edible coatings can contribute to maintaining good quality characteristics and extending mutton shelf-life. The total mesophilic counts in mutton ranged from 3.48 to 8.00 log10 CFU/g, the total psychrophilic counts from 4.00 to 9.50 log10 CFU/g, the B. thermosphacta counts from 2.30 to 7.77 log10 CFU/g and the lactic acid bacteria counts from 2.00 to 5.85 log10 CFU/g. Chitosan coatings significantly (p < 0.05) reduced the total mesophilic, the total psychrophilic (1–2 log10 cfu/g), the B. thermosphacta and the lactic acid bacteria counts in mutton. Alginate exhibited a lower L* value and a higher a* value and chroma compared with the control and chitosan lots. No significant differences were observed in the chemical composition of meat pieces among the experimental groups. Oregano oil positively affected the sensory attributes of meat. The most favourable combination, based on the microbiological counts, the organoleptic characteristics and the shelf-life extension of mutton, was that of chitosan with oregano essential oil

Effects of Chitosan Coatings on Controlling Listeria monocytogenes and Methicillin-Resistant Staphylococcus aureus in Beef and Mutton Cuts

Ruminant meat is considered to be a potent vehicle of foodborne pathogen transmission. Edible coatings are considered to be promising for enhancing meat safety. Here, edible chitosan membranes were applied to whole cuts of beef and mutton to test the survival of the pathogenic bacteria Listeria monocytogenes and methicillin-resistant Staphylococcus aureus. Meat pieces weighing approximately 200 g were inoculated with a cocktail of three S. aureus isolates or four L. monocytogenes isolates (6.00 log10CFU/g). The meat pieces were encased in a chitosan coating formed by immersion and incubated aerobically or vacuum-packaged in LDPE/PA/LDPE bags for up to 21 days. A decrease in both S. aureus (x = −1.95 log10CFU/g, standard error = 0.23 log10CFU/g) and L. monocytogenes counts (x = −1.07 log10CFU/g, standard error = 0.26 log10CFU/g) was observed. No significant differences were observed between L. monocytogenes-spiked beef and mutton pieces; statistically higher S. aureus counts were observed in mutton versus beef under similar treatments. Aerobic storage of meat pieces inoculated with L. monocytogenes enhanced the antibacterial effects of chitosan—a trend that was not observed in meat pieces inoculated with S. aureus. According to the results, edible chitosan membranes were effective in controlling the growth of S. aureus and L. monocytogenes

Effects of Chitosan Coatings on Controlling <i>Listeria monocytogenes</i> and Methicillin-Resistant <i>Staphylococcus aureus</i> in Beef and Mutton Cuts

Ruminant meat is considered to be a potent vehicle of foodborne pathogen transmission. Edible coatings are considered to be promising for enhancing meat safety. Here, edible chitosan membranes were applied to whole cuts of beef and mutton to test the survival of the pathogenic bacteria Listeria monocytogenes and methicillin-resistant Staphylococcus aureus. Meat pieces weighing approximately 200 g were inoculated with a cocktail of three S. aureus isolates or four L. monocytogenes isolates (6.00 log10CFU/g). The meat pieces were encased in a chitosan coating formed by immersion and incubated aerobically or vacuum-packaged in LDPE/PA/LDPE bags for up to 21 days. A decrease in both S. aureus (x = −1.95 log10CFU/g, standard error = 0.23 log10CFU/g) and L. monocytogenes counts (x = −1.07 log10CFU/g, standard error = 0.26 log10CFU/g) was observed. No significant differences were observed between L. monocytogenes-spiked beef and mutton pieces; statistically higher S. aureus counts were observed in mutton versus beef under similar treatments. Aerobic storage of meat pieces inoculated with L. monocytogenes enhanced the antibacterial effects of chitosan—a trend that was not observed in meat pieces inoculated with S. aureus. According to the results, edible chitosan membranes were effective in controlling the growth of S. aureus and L. monocytogenes

Effect of Chitosan and Alginate-Based Edible Membranes with Oregano Essential Oil and Olive Oil in the Microbiological, Physicochemical and Organoleptic Characteristics of Mutton

Edible chitosan or alginate coatings and their combinations with oregano essential oil or olive oil, have been examined for their effect on the microbiological, physicochemical and organoleptic characteristics of mutton. The results indicated that these edible coatings can contribute to maintaining good quality characteristics and extending mutton shelf-life. The total mesophilic counts in mutton ranged from 3.48 to 8.00 log10 CFU/g, the total psychrophilic counts from 4.00 to 9.50 log10 CFU/g, the B. thermosphacta counts from 2.30 to 7.77 log10 CFU/g and the lactic acid bacteria counts from 2.00 to 5.85 log10 CFU/g. Chitosan coatings significantly (p 10 cfu/g), the B. thermosphacta and the lactic acid bacteria counts in mutton. Alginate exhibited a lower L* value and a higher a* value and chroma compared with the control and chitosan lots. No significant differences were observed in the chemical composition of meat pieces among the experimental groups. Oregano oil positively affected the sensory attributes of meat. The most favourable combination, based on the microbiological counts, the organoleptic characteristics and the shelf-life extension of mutton, was that of chitosan with oregano essential oil

Characterization of Extended Spectrum Cephalosporin-Resistant <i>Escherichia coli</i> Strains Isolated from Raw Poultry Carcasses in Catering Services in Northern Greece

Antimicrobial resistance is considered a topic of utmost interest under the concept of “One Health”, having severe implications in both human and veterinary medicine. Among the antibiotic-resistant bacteria, gram-negative bacteria, especially those belonging to the order of Enterobacterales (such as Escherichia coli), hold a prominent position in terms of both virulence and possessing/disseminating antimicrobial resistance (AMR) traits. The aim of this study was to examine the presence of extended-spectrum β-lactamase producing E. coli isolates in raw poultry carcasses collected from a university club. Five hundred raw poultry skin samples were collected from the Aristotle University of Thessaloniki (AUTh) club in Thessaloniki, Greece. A total of 64% of the samples were positive for the presence of extended-spectrum β-lactamase (ESBL)-producing E. coli. The isolates were further examined for their susceptibility to selected antibiotics by the disc diffusion method and were characterized as true ESBL, as producing class C cephalosporinases (AmpC) or “of unknown etiology” by the combination disc test. The 86 of the 120 isolates (71.67%) were classified as true ESBL, 24 (20.00%) as AmpC, and 10 (8.33%) as “of unknown etiology”. The isolates were screened for the occurrence of β-lactamase genes (blaTEM, blaCTX-M, blaSHV, and blaOXA). Thirty-six isolates (32 ESBL- and 4 AmpC-phenotype) harbored both blaTEM and blaCTX-M genes, twenty-two isolates (among which 19 ESBL-phenotype and 2 AmpC-phenotype) harbored blaCTX-M only, whereas twenty-six (14 ESBL- and 12 AmpC-phenotype) isolates harbored blaTEM alone. No isolate harboring blaSHV or blaOXA was detected. The results demonstrate the existence of E. coli isolates producing extended-spectrum β-lactamases in poultry carcasses from Greece, pausing a risk for antibiotic resistance transfer to humans

Electrospun nanofiber films suppress inflammation in vitro and eradicate endodontic bacterial infection in an E. faecalis-infected Ex Vivo Human Tooth Culture Model

Treatment failure of endodontic infections and their concurrent inflammations is commonly associated with microbial persistence and reinfection, also stemming from the anatomical restrictions of the root canal system. Aiming to address the shortcomings of current treatment options, a fast-disintegrating nanofibrous film was developed for the intracanal coadministration of an antimicrobial (ZnO nanoparticles) and an anti-inflammatory (ketoprofen) agent. The electrospun films were fabricated based on polymers that dissolve rapidly to constitute the actives readily available at the site of action, aiming to eliminate both microbial infection and inflammation. The anti-inflammatory potency of the nanofiber films was assessed in an in vitro model of lipopolysaccharide (LPS)-stimulated RAW 264.7 cells after confirming their biocompatibility in the same cell line. The nanofiber films were found effective against Enterococcus faecalis, one of the most prominent pathogens inside the root canal space, both in vitro and ex vivo using a human tooth model experimentally infected with E. faecalis. The physical properties and antibacterial and anti-inflammatory potency of the proposed electrospun nanofiber films constitute a promising therapeutic module in the endodontic therapy of nonvital infected teeth. All manuscripts must be accompanied by an abstract. The abstract should briefly state the problem or purpose of the research, indicate the theoretical or experimental plan used, summarize the principal findings, and point out major conclusions