Archives in Food and Nutrition

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Short Article - Archives in Food and Nutrition (2020) Volume 3, Issue 1

Assessment of bacteriological quality of raw bulk tank Milk collected from Dairy Cattle farms in Nay Pyi Taw area by Staphylococcus Aureus and Coliforms

Thant Nyi Lin, Soe Soe Wai, Nang Khin Thuzar Aung, Wink Phyo Thu, Yamon Min Nyunt Oo, Ei Myo Thwe and Tin Tin Mying

University of Veterinary Science, Myanmar

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Keywords

Bulk tank milk, coliform bacteria, dairy cattle, petrifilm methods, Staphylococcus aureus

Introduction

Milk and dairy products are important for healthy life (Lejeune and Rajala-Schultz, 2009) and can provide good nutritive values in every sense (Food and Drug Administration, 2012). Milk products are widely consumed across the world following the rapidly growing global markets. However, on the other hand, milk can habour microorganisms including the bacteria that can be harmful to the consumers. The occurrence of milk-borne diseases can increase with high consumption of milk, particularly when appropriate hygienic measures are not taken (Singh and Prakash, 2008).

In Myanmar, there has been a sharp increase in the consumption of milk and dairy products in recent decades. Milk is primarily produced in Mandalay, Yangon and Nay Pyi Taw area, which account for 55%, 15%, and 10% of the country’s dairy cattle population, respectively According to Livestock Breeding and Veterinary Department (LBVD), the per capita consumption of milk in Myanmar has been increasing and the import of milk and dairy products alone has cost more than 100 million USD annually since 2014 (LBVD, 2017). At the same time, as the consumption increased, the morbidity of diarrhoea and dysentery caused by milk-borne pathogens has also increased. It has been reported that 5.6% of all diarrheal and dysentery cases in Myanmar were caused by milk-borne pathogens (Tin Kyu Kyu Khaing, 2008). This has made the milkborne diarrhea included in the fourth most important group of notifiable diseases of the country (Mar Mar Nyein et al., 2005; Myanmar One Health strategy, 2016, Myint, 2017).

Materials and Methods

A cross-sectional study was conducted in dairy cattle farms in Nay Pyi Taw, Myanmar. A total of 100 raw bulk tank milk (BTM) samples were collected from 50 dairy cattle farms selling milk to the markets. The sample collection was carried out separately in two seasons, from July to October 2015 during the wet season and from January to March 2016 during the dry season Approximately 100 ml of BTM sample was collected from each farm and examined for bacterial content using 3M petrifilm methods. For TBC, the enumeration of S. aureus was achieved by using staph express count plate (STX) and disc (3M Company, St. Paul, USA) methods following the AOAC 2003.08 guidelines. For CC, counting was performed with 3M petrifilm coliform plates (3M Company, St. Paul, USA) as recommended by AOAC 986.33 and 989 guidelines. All the test procedures were employed in accordance with the manufacturer’s instruction.

Results and Discussion

The occurrence of S. aureus and coliforms in BTM was observed to be 100% and 96% in the wet season and 98% and 84% in the dry season, respectively. However, despite higher occurrence during the wet season, no statistically significant association was found between the seasons and occurrence of bacteria.

The average count of S. aureus in BTM was 2.6×109 cfu/ml in the wet season and 13.9×108 cfu/ml in dry season. It was higher than the findings of Khin Zar Linn (2015) in Nay Pyi Taw area whose mean value for bacterial load was 2.67×108cfu/ml in BTM. It was also higher than the mean value of TBC in a recent study in Mandalay Region, Myanmar, which was 2.5×107cfu/ml, (Ye Wint Naing et al., 2019). However, it is to note that since S. aureus could be potentially hazardous when higher than 104 cfu/ml in milk (Anonymous, 1996; Han et al., 2005), all the milk samples in this study, as well as those in previous studies, appeared to be potentially risky to consumers, implying that the contamination started at farm levels and the needs of good hygienic measures to reduce the bacterial load in BTM.

For coliforms, the mean value of counts in BTM was 2.05×109 cfu/ml in the wet season and 1.75×109 cfu/ml in the dry season. A similar study conducted in Mandalay Region, Myanmar reported a lower percentage of coliform contents in raw BTM at the level of 1.59×105cfu/ml (Ye Wint Nang, et al., 2019). Therefore, in comparison with contemporary studies on raw BTM in Myanmar, the bacterial load in this study was higher both in terms of TBC and CC. The presence of positive correlation between TBC and CC (Ye Wint Naing et al., 2019) could be a factor relating to the high percentage of CC in BTM.

In this study, the high percentage of S. aureus in BTM might be attributable to low hygienic conditions during milking and milk-handling, as well as due to post-milking contamination by poor management. From this finding, it seemed reasonable to assume that raw milk could become a potential source of harmful pathogens if not properly treated and that would leave the consumers vulnerable to foodborne illnesses and infections (Weigand, 2013). It highlighted the importance of milk hygiene and good manufacturing practices in relation to public health.

Conclusion

The milk samples were highly contaminated with S. aureus and coliforms bacteria that they did not meet the minimum requirement of international raw milk standards. Hence, it is recommended that farmers and producers should be aware of good hygienic practices (GHP), good animal husbandry practices (GAHP), microbiological risk assessment (MRA), hazard analysis and critical control point (HACCP) and good manufacturing procedures (GMP) to make it safe to the consumers of cow’s milk.

References