Microbial evaluation of branded and unbranded milk sold in the city of Chakdara, Dir (lower) Pakistan - A pilot study

Background: Milk is an important part of food because of its high nutritional value. This study was conducted to determine the presence of bacteria in branded (packed) and unbranded (fresh milk) samples of milk.Methods: In a pilot study, samples of branded (n=3) and unbranded (n=3) milk were investigated. Samples were stored in controlled conditions till they were inoculated on the already prepared sterile agar plates under the laminar flow cabinet. After incubation for 24 hours at 37°C, Gram staining was performed.Results: Various kind of bacteria were detected in all the selected samples. The Cocci were observed in large quantity while Bacilli and Spirilla in minute/negligible quantity. The Cocci were mostly Gram positive. Gram negative Cocci were not observed in any of the selected samples. Bacilli were observed only in one sample. The Spirilla was absent in all the selected branded and unbranded samples except one.Conclusions: Presence of bacteria in the unbranded milk samples is not of much concern but the branded milk processors claim that it has been properly sterilized and packed. However, the presence of bacteria showed that even the branded milk samples were not properly sterilized as claimed by the processors.