Salmonellosis is one of the emerging zoonotic diseases. Human infections result from contaminated raw or undercooked food. Various sources of contamination in milk are dirty udder, unhygienic handling and utensils, dirty hands of milkmen and poor quality water supply at the farm. To ensure food safety there is a dire need for the availability of valid, rapid and accredited diagnostic system. Conventional culture methods for detecting Salmonella spp. in foods needs 4–5 days. The development in molecular techniques made it possible to cut short the procedure.
The present study was conducted with the aim to evaluate the burden of Salmonella spp. in milk and milk products. In total 150 samples were collected, out of which there were 75 milk samples. These samples were collected from farm dairy herds (pooled milk) located in Harbanspura Dairy colony, Lahore. Salmonella was detected in 8 samples (11%) by conventional method.
In addition to milk samples, 75 samples of milk products were also collected from retail shops. These include 50 samples of Yogurt and 25 samples of Yogurt milk. Milk products had 6 positive samples (8%). No sample of Yogurt was detected positive for Salmonella. The reason for this is that Yogurt had only Salmonella if it is present in starter culture. Furthermore yogurt is made after frequent heating. Salmonella is killed by such continuous and vigorous heating. Yogurt milk is prepared from Yogurt along with raw milk in a separate utensil. There are chances of contamination there so it had 6 positive samples. Total 14 (9%) samples were detected in 150 samples by conventional method. It was found that Salmonella was present in raw milk samples and milk products at places where either cleanliness was not proper, milk handling practices
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were not up to the mark, udder was not washed before milking or overall management practices were poor.
Positive samples obtained by conventional method were further analyzed by PCR for Salmonella genus confirmation. Out of total 8 positive milk samples by conventional method, 5(62%) were confirmed as Salmonella genus. Similarly from 6 positive samples of milk products by conventional method, only 2(33%) were confirmed as of Salmonella genus. Further PCR was conducted for Salmonella typhimurium detection. Milk samples were containing 3(60%) positive samples while no positive sample was detected in milk products.
On the basis of the results of present study, it is recommended that milk should always be boiled before use. Further Hygienic measures should be adopted during milking. Proper handling of milk and milk products is also important to limit the cross contamination. It is also advised that standards such as pasteurization and HACCP should be introduced to facilitate production of good quality milk. Electronic and print media should also create awareness among people about food safety.