The objectives of study were to assess presence of Listeria monocytogenes, perform serotyping and investigate antibiotic resistance in raw milk and dairy products. A total of 210 milk and dairy products including white (n = 20) and kashar cheese (n = 20), ice cream (n = 20), butter (n = 20), cokelek (n = 10), kuymak (n = 10) and farm cheese (n = 10) were obtained from Samsun, Turkey. All samples were analyzed using an immunomagnetic separation-based culture technique and strains of L. monocytogenes were confirmed by presence of hlyA and iap genes by polymerase chain reaction (PCR). L. monocytogenes was identified in 5 of 100 (5%) milk samples, serotyped as 4b and 1/2b, and in 9 of 110 (8.2%) dairy products, serotyped as 1/2a, 1/2b and 1/2c. However, L. monocytogenes was not identified from butter, kashar and ice cream samples. The antibiotic susceptibility against ampicillin, amoxicillin/clavulanic acid, erythromycin, chloramphenicol, penicillin G, oxytetracycline, tetracycline and vancomycin was assessed by disc diffusion method. It was found that 15.3% of isolates were resistant to at least one drug and 36.5% were multidrug resistant. Among isolates, resistance to tetracycline was most commonly encountered (34.6%), followed by resistance to chloramphenicol (25%) and penicillin G (23%). In conclusion, our data also indicate that consuming raw and unpasteurised milk and dairy products could pose a risk of listeriosis in humans.

The aim of this study was to investigate the prevalence of enterotoxigenic Staphylococcus aureus in 122 samples, including 60 raw milk, 32 white cheese, 10 kashar cheese, 10 butter, and 10 ice cream samples obtained from Samsun province, Turkey. In this study, S. aureus was detected in 64 samples, including raw milk (45/60; 75%), white cheese (12/32; 37.5%), kashar cheese (3/10; 30%), butter (3/10; 30%), and ice cream (1/10; 10%) samples. A total of 81 isolates were identified as S. aureus by PCR with the presence of 16S rRNA and nuc genes. The presence of genes encoding the staphylococcal enterotoxins (SEs) SEA, SEB, SEC, and SED was detected by multiplex PCR. According to the analysis, seven isolates from the raw milk samples (7/51; 13.7%) were enterotoxigenic; five of them produced SEA (5/7; 71.4%), one produced SEB (1/7; 14.2%), and one produced SEA+SEB (1/7; 14.2%). Four isolates from the white cheese samples (4/21; 19%) produced the SEA (1/4; 25%), SEC (1/4; 25%), SED (1/4; 25%), and SEA+SED (1/4; 25%) toxins. Two isolates from the kashar cheese samples (2/4; 50%) were found to be enterotoxigenic; one produced SEA (1/2; 50%) and the other produced SED (1/2; 50%). One isolate from the butter samples (1/4; 25%) showed enterotoxigenic character (SEB, 1/1; 100%). The products were found to be potentially hazardous to public health because of the fact that levels of contamination were higher than 105-106 cfu/g ml in 39% (25/64, 17 raw milk, 7 white cheese, and 1 butter) of the analyzed samples.

The genetic diversity of 168 Campylobacter jejuni isolates originating from human (n=30), cattle (n=36), sheep (n=44), dog (n=35), and poultry (n=21) and cdt genes prevalence of the isolates were investigated. To determine the genetic diversity of these strains, random amplified polymorphic DNA-polymerase chain reaction (PCR) using a random primer (M13) was performed. The numbers of genotypes determined in human, cattle, sheep, dog, and poultry isolates were 19, 18, 17, 18, and 6, respectively. To find out the prevalence of cdt genes in C. jejuni isolates simultaneously, a multiplex PCR was performed. The prevalence of the separate cdt genes was found to vary from 69% to 100% for cdtA, 92% to 100% for cdtB, and 39% to 98% for cdtC. These rates without host discriminating were 95%, 98%, and 93% for cdtA, cdtB, and cdtC, respectively. The prevalence of all three cdt genes in strains originating from human, cattle, sheep, dog, and poultry were 87%, 67%, 84%, 89%, and 39%, respectively. These results showed the relatively high genetic heterogeneity and variation of cdt genes among C. jejuni isolates from various sources except for poultry isolates. This study gives baseline data on molecular characterization of C. jejuni strains from different sources.

The aim of this study was to determine the prevalence of enterotoxigenic and methicillin-resistant Staphylococcus aureus in ice creams. After culture-based identification of isolates, the presence of 16S rRNA and nuc was confirmed by mPCR. S. aureus was identified in 18 of 56 fruity (32.1%), 4 of 32 vanilla (12.5%), and 1 of 12 chocolate (8.3%) ice creams. S. aureus was identified as 38 isolates in 23 ice cream samples by culture-based techniques, but only 35 isolates were confirmed by PCR as S. aureus. To determine the enterotoxigenic properties of PCR-confirmed S. aureus isolates, a toxin detection kit was used (SET RPLA®). Of the 12 enterotoxigenic S. aureus isolates, 9 SEB (75%), 1 SED (8.3%), 1 SEB+SED (8.3%), and 1 SEA+SEB+SED (8.3%) expressing isolates were found. The presence of enterotoxin genes (sea, seb, sed) was identified in 13 (37.1%) out of 35 isolates by the mPCR technique. In the ice cream isolates, the sea, seb, and sed genes were detected: 1 sea (7.6%), 9 seb (69.2%), 1 sed (7.6%), 1 seb+sed (7.6%), and 1 sea+seb+sed (7.6%), respectively. The sec gene was not detected in any of these isolates. One of the 35 (2.8%) S. aureus strain was mecA positive.

The objective of this study was to determine the effects of different pretreatment agents such as chitosan (0.5% (w/v), pH 2.9-3.2) and lactic acid (0.5% (v/v), pH 2.5-2.7) on the chemical and sensory qualities of mussels stored at 4ºC. Mussels were dipped in 100 mL of 0.5% solution of lactic acid (v/v) and chitosan (w/v) at room temperature (22ºC) for 15 min. Mussels from the control group were dipped in 100 mL of sterile distiled water (2% NaCl) without chitosan and lactic acid. Treatment of mussels with lactic acid and chitosan at the beginning of the experiment (day 0) for 15 min reduced bacterial counts of total aerobic mesophilic bacteria (0.53-1.07 log) psychrotrophic bacteria (0.11-0.13 log), Lactobacillus spp. (0.46-1.30 log), Enterobacteriaceae (0.43-0.48 log) and coliform bacteria (0.52-0.66 log). Total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA), trimethylamine nitrogen (TMA-N) and histamine values of control group mussels were increased from (day 0) 13.1 mg N 100 g , 4.86 mg N 100 g -1 and 7.75 ppm at the end of the storage period (day 11), respectively (P<0.05). The results indicated that shelf-life of mussels stored at 4ºC were limited to 4 days in the control group. However, mussels pretreated with lactic acid and chitosan were stored for 6-7 days and the shelf-life of mussels was extended for ca. 2-3 days, as compared with the control group (P<0.05).