scholarly journals The prevalence of Listeria monocytogenes and Staphylococcus aureus and their virulence genes in bulk tank milk in Kosovo

2017 ◽  
Vol 11 (03) ◽  
pp. 247-254 ◽  
Author(s):  
Ibrahim Mehmeti ◽  
Hysen Bytyqi ◽  
Skender Muji ◽  
Ingolf F Nes ◽  
Dzung B Diep

Introduction: Milk is considered to be a healthy, nutritious food product. Microbiological quality is an important aspect in evaluating the quality of milk. Methodology: A total of 603 bulk tank milk samples from 221 farms distributed across ten different regions were collected for milk quality assessment. Quality was judged by total viable count, and the prevalence of two foodborne pathogens (Listeria monocytogenes and Staphylococcus aureus) by using selective media and 16S rRNA gene sequencing. The presence of virulence genes was detected by polymerase chain reaction (PCR) using specific primers. Results: Milk from only 7% (15/221) of farms were found to comply with the European Union standard. Interestingly, the microbiological quality of milk from the larger herd size farms (more than 10 cows) was better than in smaller herds. L. monocytogenes was found in 2.7% (6/221) of farms, and all the examined L. monocytogenes isolates were positive with respect to the virulence genes prfA, actA, and hlyA. S. aureus was found in 39.8% (88/221) of the farms. In total, 30.7% (27/88) of the staphylococci were positive for enterotoxin production. The enterotoxins identified were toxin B (40.7%), toxin D (33.4%), toxin C (18.5%), and toxin A (7.4%). Conclusions: The total number of bacteria in milk was very high. The presence of two foodborne pathogens in raw milk represents a great health risk to consumers. To improve the microbial quality of milk in Kosovo, important measures to improve hygiene, including better information, guidance, and control, are needed.

2008 ◽  
Vol 71 (2) ◽  
pp. 325-332 ◽  
Author(s):  
YONG-SUK KIM ◽  
ZIAN-BIN ZHENG ◽  
DONG-HWA SHIN

Kimchi is a unique Korean traditional vegetable product that is fermented by lactic acid bacteria (LAB) and is mainly consumed as a side dish with boiled rice. Its main ingredients are brined Chinese cabbage, red pepper powder, and fermented fish sauce, and these are combined with many spices such as garlic, green onion, ginger, and some seaweed. The relationship between the concentration of LAB or the pH and the growth of three gram-positive foodborne pathogens (Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus) was evaluated. Heat treatment (HT; 85°C for 15 min) or neutralization treatment (NT; pH 7.0) was conducted on day 0 (0-D group) and day 3 (3-D group) of incubation. The pH in the control group and the NT group dropped sharply to 4.12 to 4.30 after 2 days of incubation and slightly decreased thereafter, whereas the pH in the control group and HT group stayed at 7.0 during incubation. LAB were not detected in the HT kimchi during incubation. B. cereus in the NT-0-D, NT-3-D, and HT-3-D groups was reduced by 1.5 to 3.1 log CFU/ml but increased slightly in the HT-0-D group. L. monocytogenes in HT-3-D and NT-3-D groups disappeared after 5 days of incubation, and S. aureus in the NT-0-D group disappeared after 4 days. These findings indicate that growth of all the foodborne pathogens was inhibited by NT-0-D, HT-3-D, and NT-3-D, but B. cereus was not inhibited by HT-0-D. Thus, growth of LAB in kimchi is an important factor in the control of foodborne pathogens.


2012 ◽  
Vol 95 (8) ◽  
pp. 4275-4279 ◽  
Author(s):  
B.E. Gillespie ◽  
M.J. Lewis ◽  
S. Boonyayatra ◽  
M.L. Maxwell ◽  
A. Saxton ◽  
...  

2021 ◽  
Author(s):  
Hye-Ri Jung ◽  
Young Ju Lee

Abstract Background: Staphylococcus aureus, a persistent and chronic mastitis-causing pathogen, produces various virulence factors, including enterotoxins. This study analyzed the genetic characteristics of bovine mastitis-related virulence factors to evaluate potential pathogenesis in S. aureus isolated from bulk tank milk.Results: Among 93 S. aureus isolates from 396 dairy farms in six factories operated by three dairy companies in Korea, 40 (43.0%) isolates carried at least one or more enterotoxin genes and there were significant differences between factories within the same company (p < 0.05). Moreover, S. aureus carrying enterotoxin genes showed a higher prevalence in all virulence genes tested in this study except for pvl and lukM, which were not detected in any isolate, than the isolates without enterotoxin genes. In particular, the prevalence of six genes (hla, hlb, lukED, fnbA, clfA, and clfB) was significantly higher in S. aureus carrying enterotoxin genes than isolates without enterotoxin genes (p < 0.05). The most common multilocus sequence type (ST) of 40 enterotoxin-producing isolates was ST188, and all isolates of ST188 harbored the see gene. However, none of the isolates of ST1 and ST72 carried the see gene, and all isolates of ST1 carried the seh gene.Conclusions: Although S. aureus isolated from bulk tank milk, not from mastitis, had a high prevalence of enterotoxins and virulence factors simultaneously, posing a public health threat. Moreover, high enterotoxins in bulk tank milk may be reflected by poor hygiene; therefore, it is important to develop strong monitoring and sanitation programs to ensure that dairy factories produce hygienic milk.


2006 ◽  
Vol 34 (1) ◽  
pp. 755-758
Author(s):  
F. Peles ◽  
P. Keresztúri ◽  
A. Iglói ◽  
A. Szabó

1998 ◽  
Vol 61 (8) ◽  
pp. 1052-1056 ◽  
Author(s):  
MAIJA HATAKKA

The microbiological quality of 1,012 hot meals served on aircraft was studied in 1991 to 1994. The material included dishes prepared in 33 countries all over the world. The geometric means of aerobic colony counts and Escherichia coli were significantly lower in breakfasts (P &lt; 0.05) than in main dishes. Pathogenic bacteria were found in 30 samples (3.0%), Bacillus cereus being the most common pathogen. The frequencies of B. cereus and Staphylococcus aureus did not differ between breakfasts and main dishes. Many of the samples exceeded the minimum acceptable microbiological standards recommended by the Association of European Airlines (AEA) for E. coli, S. aureus, B. cereus, Clostridium perfringens, and Salmonella; i.e., 8.2%, 0.6%, 0.7%, 0.7% and 0.3%, respectively. There were considerable differences in aerobic colony counts and E. coli counts between countries where the food was prepared.


Author(s):  
Ricardo Jiovanni Soria-Herrera ◽  
Karla Gabriela Dominguez-Gonzalez ◽  
Rebeca Rumbo-Pino ◽  
Arizbeth Piña-Lazaro ◽  
Jose Jesus Alvarez-Perez ◽  
...  

This study investigated the presence of nontuberculous mycobacteria (NTM) for the first time in two types of unpasteurized fresh cheese produced in the state of Michoacan, Mexico. We tested for this pathogen along with the others to broaden the study of microbiological quality in a total of 60 samples of cheese, 30 fresh and 30 adobera, which were collected from six artisanal cheese factories (ACF). The hygienic conditions of these establishments and the practices of cheese manufacture were generally poor. Although Mycobacterium bovis was not detected, four cheese samples harbored NTM isolates. The four NTM isolates were identified using three molecular markers (hsp65, rrs and rpoB genes) which corresponded to Mycolicibacterium fortuitum (n=3) and Mycolicibacterium mageritense (n=1). All 60 cheese samples analyzed had unsatisfactory microbiological quality according to the Mexican Official Guideline. Regarding fresh cheeses, all 30 samples analyzed were positive for aerobic mesophilic bacteria (AMB), total coliforms (TC), fecal coliforms (FC) and yeasts and moulds. Escherichia coli and Staphylococcus aureus were present in 23 and 21 samples, respectively. Listeria monocytogenes was identified in a sample and was isolated from a bulk milk tank in the same ACF. With regard to adobera cheeses, all samples were positive for AMB, TC, FC, yeasts and moulds and S. aureus. E. coli was isolated from 28 samples. Salmonella was isolated from a sample and also from a wooden shovel used in the manufacture of the cheeses in the same ACF. Thus, the consumption of unpasteurized fresh cheese may represent a public health risk. Because of this, health authorities should enforce the legislation that forbids the processing of cheese with unpasteurized milk and encourage producers to follow good manufacturing practices from original ingredients all the way through the production process of the cheese to its sale, in order to assure a safe product.


2004 ◽  
Vol 67 (8) ◽  
pp. 1779-1781 ◽  
Author(s):  
S. SERRANO ◽  
L. M. MEDINA ◽  
M. JURADO ◽  
M. JODRAL

Hygienic quality was investigated in 60 samples of ready-to-eat snails (Helix lactea, Helix nemoralis, and Helix hortensis) obtained from 30 in-season street stalls and 30 catering establishments (bars) in Córdoba. In accordance with Spanish legislation regarding hygiene in the preparation, distribution, and sale of prepared foods, counts were obtained for total mesophilic aerobic bacteria, coliforms, total Enterobacteriaceae, Escherichia coli, Salmonella, and Staphylococcus aureus. The results obtained showed that 33.3, 20.0, and 13.3% of the samples from stalls and 73.3, 53.3, and 6.7% of the samples from bars did not comply with the regulations with respect to the control of total mesophilic aerobic bacteria, Enterobacteriaceae, and Staphylococcus aureus, respectively. Coliforms were found in 53.3% of the samples from the bars (mean, 2.1 CFU/g) and in 33.3% of the stalls (mean, 1.1 CFU/g). Salmonella was not detected.


BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Kruthika Patel ◽  
Sandra M. Godden ◽  
Erin E. Royster ◽  
Brian A. Crooker ◽  
Timothy J. Johnson ◽  
...  

Abstract Background Colonization of dairy cows by Staphylococcus aureus (S. aureus), especially those which are multi-drug resistant and toxin producing, is a concern for animal health and well-being as well as public health. The objective of this study was to investigate the prevalence, antibiotic resistance, gene content and virulence determinants of S. aureus in bulk tank milk samples (BTM) from U.S. dairy herds. Results BTM samples were collected, once in winter and once in summer, from 189 U.S. dairy herds. Of 365 BTM samples cultured, the sample and herd prevalence of S. aureus in BTM was 46.6% (170 of 365 samples) and 62.4% (118 of 189 herds), respectively. Among a subset of 138 S. aureus isolates that were stored for further analysis, 124 were genome sequenced after being confirmed as S. aureus using phenotypic tests. The most commonly identified antimicrobial resistance-associated gene was norA (99.2%) and mecA gene responsible for methicillin resistance (MRSA) was identified in one isolate (0.8%). The most frequently detected putative virulence genes were aur (100%), hlgB (100%), hlgA, hlgC, hlb (99.2%), lukE (95.9%) and lukD (94.3%). In the 53 staphylococcal enterotoxin positive isolates, sen (37.9%), sem (35.5%), sei (35.5%) and seg (33.1%) were the most frequently detected enterotoxin genes. Among the 14 sequence types (ST) and 18 spa types identified, the most common was ST2187 (20.9%) and t529 (28.2%), respectively. The most predominant clone was CC97 (47.6%) followed by CC unknown (36.3%). The single MRSA isolate belonged to ST72-CC8, spa type t126 and was negative for the tst gene but harbored all the other virulence genes investigated. Conclusion Our findings indicated a high prevalence of S. aureus in BTM of U.S. dairy herds, with isolates showing little evidence of resistance to antibiotics commonly used to treat mastitis. However, isolates often carried genes for the various enterotoxins. This study identified predominant genetic clones. Despite lower prevalence, the presence of MRSA and multi-drug resistant strains in BTM poses a significant risk to animal and public health if their number were to increase in dairy environment. Therefore, it is necessary to continuously monitor the use of antibiotics in dairy cows.


1988 ◽  
Vol 55 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Charles H. McKinnon ◽  
A. John Bramley ◽  
Steven V. Morant

SummaryThe development of devices to sample milk at the clawpiece and at the end of the pipeline during milking are described. The results of tests to compare the bacteriological and compositional quality of milk collected from the sampling devices or from the recorder jar or milk cans were similar, demonstrating that the samples provided accurate and representative values. The use of the in-line sampling technique, whereby samples of the milk are taken at three points during its passage through the milking plant, to assess accurately the sources of bacterial contamination of bulk tank milk on farms is discussed.


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