Prevalence and characterization of pathogenic bacteria in bulk tank raw milk, Thailand

Chanida Kupradit, Sasidhorn Innok, Jirayus Woraratphoka, Mariena Ketudat-Cairns


There are numerous numbers of raw milk collection centers in Nakhon Ratchasima but lack information of the isolation and characterization of foodborne pathogens in raw milk. Therefore, the purpose of this research was to investigate the prevalence and characterization of foodborne pathogens including Bacillus cereus, Escherichia coli, Listeria monocytogenes, Salmonella spp. and Staphylococcus aureus from 33 raw milk samples from 9 different raw milk collection centers located in 8 districts in Nakhon Ratchasima, Thailand, between January to March 2016. Contaminations of L. monocytogenes and Salmonella spp. were not detected in any of the raw milk sample tested. The prevalence of B. cereus, E. coli, and S. aureus in raw milk samples were found to be 9 % (10 – 2.0 × 104 CFU/ml), 42.4 %, and 54 % (85 – 2.7 × 104 CFU/ml), respectively. The distribution of virulence genes were tested in B. cereus and S. aureus using gene specific primers by polymerase chain reaction. Out of the 29 analyzed coagulase-positive S. aureus isolates, 27 isolates (93 %) were positive for eap gene amplification and 14 isolates (48 %) showed amplicon of eap gene and all 5 enterotoxin genes including seG, seGV, seI, seIV, and seM genes. All 8 B. cereus isolates tested showed positive PCR result with enteroxin FM (entFM) gene but negative with hemolysin gene (hblA and hblD genes) amplifications. It was inferred from these studies that bulk tank milk is a potential source of S. aureus and B. cereus in milk.


foodborne pathogens, raw milk, raw milk collection center, virulence genes


JS Van Kessel, JS Karns, L Gorski, BJ McCluskey and ML Perdue. Prevalence of Salmonellae, Listeria monocytogenes and fecal coliforms in bulk tank milk on US Dairies. J. Dairy Sci. 2004; 87, 2822–30.

R Dewanti-Hariyadi and D Gitapratiwi. Prevalence of foodborne diseases in South East and Central Asia. In: Y Motarjemi, G Moy, E Cameron, D Todd (ed.). Encyclopedia of Food Safety. 1st ed. Elsevier Science & Technology, San Diego, 2014, p. 287-94.

FY Chye, A Abdullah and MK Ayob. Bacteriological quality and safety of raw milk in Malaysia. Food Microbiol. 2004; 21, 535-41.

M Bartoszewicz, BM Hansen and I Swiecicka. The members of the Bacillus cereus group are commonly present contaminants of fresh and heat-treated milk. Food Microbiol. 2008; 25, 588–96.

RA Ombarak, A Hinenoya, SP Awasthi, A Iguchi, A Shima, ARM Elbagory and S Yamasaki. Prevalence and pathogenic potential of Escherichia coli isolates from raw milk and raw milk cheese in Egypt. Int. J. Food Microbiol. 2016; 221, 69-76.

SP Oliver, BM Jayarao and RA Almeida. Foodborne pathogens in milk and the dairy farm environment: food safety and public health implications. Foodborne Pathog. Dis. 2005; 2(2), 115-29.

United States Food and Drug Administration. Bacteriological analytical manual / Food and Drug Administration, 8th ed. MD: AOAC International, Gaithersburg, 1998.

JG Cappuccino and N Sherman. Microbiology:a laboratory manual, 5th ed. Benjamin/Cummings Science, California. 1998, p. 470.

C Kupradit, S Rodtong and M Ketudat-Cairns. Development of a DNA macroarray for simultaneous detection of multiple foodborne pathogenic bacteria in fresh chicken meat. World J. Microb. Biot. 2013; 29(12), 2281–91.

C Kupradit, S Innok, J Woraratphoka and M Ketudat-Cairns. Novel multiplex PCR assay for rapid detection of five bacterial foodborne pathogens. Suranaree J. Sci. Technol. 2017; 24(1), 41-50.

M Hussain, CV Eiff, B Sinha, I Joost, M Herrmann, G Peters and K Becker. eap gene as novel target for specific identification of Staphylococcus aureus. J. Clin. Microbiol. 2008; 46(2), 470-76.

J Chen and MW Griffiths. PCR differentiation of Escherichia coli from other gram-negative bacteria using primers derived from the nucleotide sequences flanking the gene encoding the universal stress protein. Lett. Appl. Microbiol. 1998; 27(6), 369-71.

JC Brooks, B Martinez, J Stratton, A Bianchini, R Krokstrom and R Hutkins. Survey of raw milk cheeses for microbiological quality and prevalence of foodborne pathogens. Food Microbiol. 2012; 31, 154-8.

FM Kivaria, JPTM Noordhuizen and AM Kapaga. Evaluation of the hygienic quality and associated public health hazards of raw milk marketed by smallholder dairy producers in the Dar es Salaam region, Tanzania. Trop. Anim. Health Pro. 2006; 38, 185–94.

P Padungtod and JB Kaneene. Salmonella in food animals and humans in northern Thailand. Int. J. Food Microbiol. 2006; 108(3), 346-54.

O Aygun and S Pehlivanlar. Listeria spp. in the raw milk and dairy products in Antakya,Turkey. Food Control. 2006; 17, 676-9.

S Jami, A Jamshidi and S Khanzadi. The presence of Listeria monocytogenes in raw milk samples in Mashhad, Iran. Iran. J. Vet. Res. 2010; 11(4), 363-67.

DM Bianchi, A Barbaro, S Gallina, N Vitale, L Chiavacci, M Caramelli and L Decastelli. Monitoring of foodborne pathogenic bacteria in vending machine raw milk in Piedmont, Italy. Food Control. 2013; 32, 435-9.

F Haghi, H Zeighami, G Naderi, A Samei, S Roudashti, S Bahari and P Shirmast. Detection of major food-borne pathogens in raw milk samples from dairy bovine and ovine herds in Iran. Small Ruminant Res. 2015; 131, 136-40.

RM Kamal, MA Bayoumi and SFA Abd El Aal. MRSA detection in raw milk, some dairy products and hands of dairy workers in Egypt, a mini-survey. Food Control. 2013; 33, 49-53.

VLM Rall, FP Vieira, R Rall, RL Vieitis, A Jr. Fernandes, JMG Candeias, KFG Cardoso and JP Jr. Araújo. PCR detection of staphylococcal enterotoxin genes in Staphylococcus aureus strains isolated from raw and pasteurized milk. Vet. Microbiol. 2008; 132(3-4), 408-13.

H Jamali, M Paydar, B Radmehr, S Ismail and A Dadrasnia. Prevalence and antimicrobial resistance of Staphylococcus aureus isolated from raw milk and dairy products. Food Control. 2015; 54, 383-88.

D Kanungpean, J Rujit, J Chanda, N Boonyaprapa, P Tonchotiwetch, W Mahanil, A Tain and A Intarapuk. The quality testing of raw goat’s milk in Nongchok District, Bangkok. J. Mahanakorn Vet. Med. 2014; 9(2), 83-8.

T Chitov, R Dispan and W Kasinrerk. Incidence and diarrhegenic potential of Bacillus cereus in pasteurized milk and cereal products in Thailand. J. Food Safety. 2008; 28(4), 467-81.

MA Abdou, NM Awny and AAEM Abozeid. Prevalence of toxicogenic bacteria in some foods and detection of Bacillus cereus and Staphylococcus aureus enterotoxin genes using multiplex PCR. Ann. Microbiol. 2012; 62, 569–80.

S Kumari and PK Sarkar. Prevalence and characterization of Bacillus cereus group from various marketed dairy products in India. Dairy Sci. Technol. 2014; 94, 483–97.

A Tewari and S Abdullah. Bacillus cereus food poisoning: international and Indian perspective. J. Food Sci. Tech. 2015; 52(5), 2500–11.

S Kumari and P Sarkar. Bacillus cereus hazard and control in industrial dairy processing environment. Food Control. 2016; 69, 20-9.

MC Te Giffel, A Wagendorp, A Herrewegh and F Driehuis. Bacterial spores in silage and raw milk. Anton. Van. Leeuw. 2002; 81, 625–30.

MTM Montanhini, R Montanhini Neto and LS Bersot. Enterotoxingenic potential of Bacillus cereus strains isolated from dairy products at different incubation temperature. Int. Food Res. J. 2015; 22(3), 1315-17.

J Kovac, RA Miller, LM Carroll, DJ Kent, J Jian, SM Beno and M Wiedmann. Production of hemolysin BL by Bacillus cereus group isolates of dairy origin is associated with whole-genome phylogenetic clade. BMC Genomics. 2016; DOI: 10.1186/s12864-016-2883-z.

K Hunt, J Schelin, P Rådström, F Butler and K Jordan. Classical enterotoxins of coagulase-positive Staphylococcus aureus isolates from raw milk and products for raw milk cheese production in Ireland. Dairy Sci. Technol. 2012; 92, 487–99.

R Nazari, H Godarzi, FR Baghi and M Moeinrad. Enterotoxin gene profiles among Staphylococcus aureus isolated from raw milk. Iran. J. Vet. Res. 2014; 15(4), 409–12.

B Khaenda, W Namwat, D Kotimanusvanij and C Chomvarin. Distribution of new Staphylococcal enterotoxin genes (seg, seh, sei, sej, and sel) in Staphylococcus aureus isolated from retail ready-to-eat foods in the Northeast Thailand. Srinagarind Med. J. 2016; 31(4), 237-44.

G Blaiotta, D Ercolini, C Pennacchia, V Fusco, A Casaburi, O Pepe and F Villani. PCR detection of staphylococcal enterotoxin genes in Staphylococcus spp. strains isolated from meat and dairy products. Evidence for new variants of seG and seI in S. aureus AB-8802. J. Appl. Microbiol. 2004; 97, 719–30.

A Tewari, SP Singh and R Singh. Incidence and enterotoxigenic profile of Bacillus cereus in meat and meat products of Uttarakhand, India. J. Food Sci. Tech. 2015; 52(3), 1796-801.

JL McKillip. Prevalence and expression of enterotoxins in Bacillus cereus and other Bacillus spp., a literature review. Anton. Van. Leeuw. 2000; 77, 393–99.


  • There are currently no refbacks.

Online ISSN: 2228-835X

Last updated: 20 June 2019