Occurrence and antibiotic resistance of enterotoxigenic Staphylococcus aureus in raw ovine and caprine milk in Greece

International audienceAbstractOvine (n = 140) and caprine (n = 35) raw bulk tank milk samples from farms in central Greece were examined for the occurrence of enterotoxigenic Staphylococcus aureus. The S. aureus isolates were screened for staphylococcal enterotoxin (SE) production, the presence of enterotoxin genes, antibiotic resistance (AR), and methicillin resistance. S. aureus was isolated from 24.3% and 31.4% of ovine and caprine milk samples, respectively. Among the S. aureus isolates of ovine milk (n = 34) and caprine (n = 11) milk, the enterotoxigenic (SEA-SED) isolates were 21 (61.8%) and 7 (63.6%) for the ovine and caprine milk, respectively. Most toxigenic isolates harbored more than one toxin gene and a total of 11 distinct toxinotypes were detected. The most frequent toxin-gene combinations were “sec, tst” (8 isolates), “seb, seg, sei, tst” (4), “seb, seg, sei” (3), and “seb” (3). Six isolates displayed multiple AR towards up to five antimicrobials. Among ovine milk isolates, the highest resistance frequency was observed towards erythromycin (11.8% of the isolates) and tetracycline (8.8%). Among caprine milk isolates, the most frequent resistance was observed towards erythromycin (18.2%). One methicillin-resistant S. aureus (MRSA) isolate was detected in an ovine milk sample and belonged to spa type t4038. This spa type has been isolated for the first time in Greece and, to our knowledge, has not been previously reported among MRSA isolates from raw milk or dairy products worldwide

The antimicrobial effect of herbs essential oils and nisin added in beef meat

The antimicrobial effect of oregano, thyme, rosemary essential oils and their mixture, nisin at 500 or 1000 IU/g, and their combinations, on L. monocytogenes, S. aureus, E. coli O157:H7 and Salmonella in tryptic soy broth (TSB) during incubation at 37 o C for 32 h was weak at the concentration of 0.3%, but high at the levels of 0.6 and 0.9%. Due to strong antimicrobial activity presented by the essential oils at 0.6 and 0.9% in TSB, the synergistic activity against the tested pathogens was only evident for the combinations with nisin at 500 or 1000 IU/g and the essential oils at 0.3%. Sensory evaluation revealed that the organoleptic properties of minced beef meat treated with oregano, thyme, rosemary essential oils and their mixture at the supplementation levels of 0.3 and 0.6% and also oregano at 0.9% were acceptable by the panelists. In contrast, the organoleptic properties of thyme, rosemary essential oils and the mixture of all the essential oils at 0.9% were not acceptable by the panelists. The antibacterial efficacy of all the essential oils at 0.3% in minced beef meat was not examined, since pertinent results in TSB showed a weak antibacterial activity against the examined pathogens, whereas the addition of thyme, rosemary and the mixture of the essential oils at 0.9% were also not examined because organoleptic study showed unacceptable organoleptic properties in minced meat. The antimicrobial effect against L. monocytogenes, S. aureus, E. coli O157:H7 and Salmonella of the essential oils, nisin and their combinations were studied in minced beef meat during refrigerated storage at 4 or 10 οC 12 days and were studied in the following treatment groups: · No addition of essential oils, nisin or their combinations · Addition of oregano essential oil at 0.6 or 0.9%, thyme essential oil at 0.6%, rosemary essential oil at 0.6% or their mixture at 0.6%, · Addition of nisin at 500 or 1000 IU/g and · Addition of combinations of oregano essential oil at 0.6 or 0.9%, thyme essential oil at 0.6%, rosemary essential oil at 0.6% or their mixture at 0.6% with nisin at 500 or 1000 IU/g,Η αντιμικροβιακή δράση της προσθήκης των αιθέριων ελαίων ρίγανης, θυμαριού, δενδρολίβανου και μίγματός τους κατά των παθογόνων L. monocytogenes, S. aureus, E. coli O157:H7 και Salmonella σε θρεπτικό ζωμό στους 37 o C για 32 ώρες ήταν ασθενής σε συγκέντρωση 0.3%, ενώ ήταν ισχυρή στις συγκεντρώσεις 0.6 και 0.9%. Η συνεργός αντιμικροβιακή δράση κατά των εξετασθέντων παθογόνων της προσθήκης των συνδυασμών των αιθέριων ελαίων με τη νισίνη (500 ή 1000 IU/ml) ήταν εμφανής κατά κύριο λόγο στη συγκέντρωση 0.3% των αιθέριων ελαίων. Τα εξετασθέντα οργανοληπτικά χαρακτηριστικά (οσμή, γεύση και συνολική αποδοχή) της προσθήκης των αιθέριων ελαίων ρίγανης, θυμαριού, δενδρολίβανου και μίγματός τους (σε ίσες αναλογίες) σε συγκεντρώσεις 0.3 και 0.6% και της ρίγανης 0.9% παρέμειναν αποδεκτά από τους δοκιμαστές καθ’ όλη τη διάρκεια της συντήρησης στην ψύξη, σε αντίθεση με εκείνα της προσθήκης των αιθέριων ελαίων θυμαριού, δενδρολίβανου και του μίγματος των αιθέριων ελαίων σε συγκεντρώσεις 0.9% που δεν ήταν αποδεκτά. Για όλα τα αιθέρια έλαια οι συγκεντρώσεις 0.3% δεν επιλέχθηκαν να μελετηθούν στο μυττωτό βοείου κρέατος, γιατί παρουσίασαν ασθενή αντιμικροβιακή δράση στο TSB, ενώ αντίστοιχα για τα αιθέρια έλαια θυμαριού, δενδρολίβανου και του μίγματος των αιθέριων ελαίων οι συγκεντρώσεις 0.9% δεν επιλέχθηκαν, γιατί εμφάνισαν οργανοληπτικά χαρακτηριστικά που δεν ήταν αποδεκτά στον οργανοληπτικό έλεγχο. Η μελέτη της αντιμικροβιακής δράσης της προσθήκης των αιθέριων ελαίων, της νισίνης και του συνδυασμού τους σε «στείρο» μυττωτό βόειου κρέατος κατά στελεχών των παθογόνων L. monocytogenes, S. aureus, E. coli O157:H7 και Salmonella κατά τη συντήρησή του στους 4 και 10 oC για 12 ημέρες, περιελάμβανε τις εξής ομάδες: · Απουσία αιθέριου ελαίου (μάρτυρες) · της προσθήκης των αιθέριων ελαίων ρίγανης (0.6 και 0.9%), θυμαριού (0.6%), δενδρολίβανου (0.6%) και μίγματός τους (0.6 %) · της προσθήκης της νισίνης σε συγκεντρώσεις 500 και 1000 IU/g και · της προσθήκης των συνδυασμών των αιθέριων ελαίων ρίγανης (0.6 και 0.9%), θυμαριού (0.6%), δενδρολίβανου (0.6%) και μίγματός τους (0.6 %) με τη νισίνη (500 και 1000 IU/g

Ochratoxin A in Slaughtered Pigs and Pork Products

Ochratoxin A (OTA) is a mycotoxin that is produced after the growth of several Aspergillus and Penicillium spp. in feeds or foods. OTA has been proved to possess nephrotoxic, hepatotoxic, teratogenic, neurotoxic, genotoxic, carcinogenic and immunotoxic effects in animals and humans. OTA has been classified as possibly carcinogenic to humans (Group 2B) by the IARC in 2016. OTA can be mainly found in animals as a result of indirect transmission from naturally contaminated feed. OTA found in feed can also contaminate pigs and produced pork products. Additionally, the presence of OTA in pork meat products could be derived from the direct growth of OTA-producing fungi or the addition of contaminated materials such as contaminated spices. Studies accomplished in various countries have revealed that pork meat and pork meat products are important sources of chronic dietary exposure to OTA in humans. Various levels of OTA have been found in pork meat from slaughtered pigs in many countries, while OTA levels were particularly high in the blood serum and kidneys of pigs. Pork products made from pig blood or organs such as the kidney or liver have been often found to becontaminated with OTA. The European Union (EU) has established maximum levels (ML) for OTA in a variety of foods since 2006, but not for meat or pork products. However, the establishement of an ML for OTA in pork meat and meat by-products is necessary to protect human health

Ochratoxin A in Slaughtered Pigs and Pork Products

Ochratoxin A (OTA) is a mycotoxin that is produced after the growth of several Aspergillus and Penicillium spp. in feeds or foods. OTA has been proved to possess nephrotoxic, hepatotoxic, teratogenic, neurotoxic, genotoxic, carcinogenic and immunotoxic effects in animals and humans. OTA has been classified as possibly carcinogenic to humans (Group 2B) by the IARC in 2016. OTA can be mainly found in animals as a result of indirect transmission from naturally contaminated feed. OTA found in feed can also contaminate pigs and produced pork products. Additionally, the presence of OTA in pork meat products could be derived from the direct growth of OTA-producing fungi or the addition of contaminated materials such as contaminated spices. Studies accomplished in various countries have revealed that pork meat and pork meat products are important sources of chronic dietary exposure to OTA in humans. Various levels of OTA have been found in pork meat from slaughtered pigs in many countries, while OTA levels were particularly high in the blood serum and kidneys of pigs. Pork products made from pig blood or organs such as the kidney or liver have been often found to becontaminated with OTA. The European Union (EU) has established maximum levels (ML) for OTA in a variety of foods since 2006, but not for meat or pork products. However, the establishement of an ML for OTA in pork meat and meat by-products is necessary to protect human health

Aquaculture bacterial bank in Greece - methodology and first results

A collection a pathogenic bacterial strains isolated from natural disease outbreaks in Greek fish farms was founded in Greece by the cooperation of three laboratories: a) Lab. of Ichthyology, School of Veterinary Medicine, Aristotle University of Thessaloniki, b) Lab. of Ichthyopathology Faculty of Veterinary Medicine, University of Thessaly and c) Institute of Aquaculture, Hellenic Center for Marine Research Athens. This project is funded by the Hellenic Ministry of Rural Development and Food - Fisheries Department. After isolation the bacteria are characterized biochemically and molecularly (PCR). Their pathogenicity is tested using experimental challenges. Theisolates are then lyophilizised and stocked at -80 oC. The results so far indicate that Listonella anguillarum, Vibrio alginolyticus and Photobacterium damsela subsp piscicida are the main pathogens that occur in Greek mariculture

Influence of oestrus on the heat stability and other characteristics of milk from dairy goats

We examined the heat stability, somatic cell count (SCC), pH, fat, protein and lactose content of milk from goats during the oestrous period, in order to investigate evidence of possible oestrus effects on milk physical and chemical properties. Goats free from mammary infections were ranked on average SCC from three tests so that they could be stratified randomly in pairs to synchronized oestrus or left as unsynchronized non-oestrus controls. The synchronisation consisted of insertion of an intravaginal progesterone-releasing device for 17 cl, and introduction of the bucks the day of the device removal (DO). The repeated measurements analysis of variance model included the fixed effects of the experimental group (oestrus or control) and day and the corresponding interaction and also the random effect of doe. Reduced milk-heat stability, increased SCC, increased protein content and reduced pH were found in the milk samples of the oestrus group on D1, 2 and 3. The fat and lactose content of the milk was not affected by oestrus. These data indicate that the milk of goats during the mating period has reduced heat stability and, therefore, that dilution into bulk tanks should be recommended to avoid clotting when milk is intended for high thermal treatment

High Milk Somatic Cell Counts and Increased <i>Teladorsagia</i> Burdens Overshadow Non-Infection-Related Factors as Predictors of Fat and Protein Content of Bulk-Tank Raw Milk in Sheep and Goat Farms

This paper presents the results of an extensive countrywide investigation performed in 325 dairy sheep flocks and 119 goat herds throughout Greece. The objectives of the study were (a) to investigate fat and protein content in the bulk-tank raw milk of small ruminant farms in Greece and (b) to identify factors potentially influencing that content and factors that can contribute to increased content. The mean fat/protein contents in bulk-tank raw milk of sheep and goats were 6.16 ± 0.05%/4.43 ± 0.01% and 4.77 ± 0.44%/3.23 ± 0.30%, respectively. Significant differences were seen in protein content between farms in the various parts of the country. For sheep, multivariable analyses revealed breed and age of lamb removal from dams as significant for fat content, and somatic cell counts, management system in the farm, administration of anthelmintic treatment during the last stage of pregnancy, and farmer education as significant for protein content. For goats, significant factors were month into lactation period, age of kid removal from dams, and breed for fat content, and somatic cell counts, month into lactation, grazing duration, and % Teladorsagia larvae in faecal samples for protein content. For concurrently high fat and protein content, in multivariable analyses, the following emerged as significant factors: somatic cell counts in milk, numbers of parasite eggs in faeces, and veterinary collaboration (sheep), and month into lactation and somatic cell counts in milk (goats). The results indicate that high somatic cell counts in milk (reflecting the presence of mastitis) and gastrointestinal parasitic infections (mainly Teladorsagia infection) appear to exert a more significant influence on fat and protein content of milk, in comparison to non-infection-related factors

High Milk Somatic Cell Counts and Increased Teladorsagia Burdens Overshadow Non-Infection-Related Factors as Predictors of Fat and Protein Content of Bulk-Tank Raw Milk in Sheep and Goat Farms

This paper presents the results of an extensive countrywide investigation performed in 325 dairy sheep flocks and 119 goat herds throughout Greece. The objectives of the study were (a) to investigate fat and protein content in the bulk-tank raw milk of small ruminant farms in Greece and (b) to identify factors potentially influencing that content and factors that can contribute to increased content. The mean fat/protein contents in bulk-tank raw milk of sheep and goats were 6.16 &plusmn; 0.05%/4.43 &plusmn; 0.01% and 4.77 &plusmn; 0.44%/3.23 &plusmn; 0.30%, respectively. Significant differences were seen in protein content between farms in the various parts of the country. For sheep, multivariable analyses revealed breed and age of lamb removal from dams as significant for fat content, and somatic cell counts, management system in the farm, administration of anthelmintic treatment during the last stage of pregnancy, and farmer education as significant for protein content. For goats, significant factors were month into lactation period, age of kid removal from dams, and breed for fat content, and somatic cell counts, month into lactation, grazing duration, and % Teladorsagia larvae in faecal samples for protein content. For concurrently high fat and protein content, in multivariable analyses, the following emerged as significant factors: somatic cell counts in milk, numbers of parasite eggs in faeces, and veterinary collaboration (sheep), and month into lactation and somatic cell counts in milk (goats). The results indicate that high somatic cell counts in milk (reflecting the presence of mastitis) and gastrointestinal parasitic infections (mainly Teladorsagia infection) appear to exert a more significant influence on fat and protein content of milk, in comparison to non-infection-related factors