The icddr,b scientists have revealed that more than 75 per cent of all pasteurised milk available on the local market is unsafe for direct consumption.
At every stages of the dairy value chain from the farm to store, milk was found to be highly contaminated with bacteria above national and international standards, it said in a new study.
A total of 438 raw milk samples were collected from milk producers, collectors, chilling plants, local restaurants in the northern part of Bangladesh.
Ninety-five more samples were collected from commercially processed milk found on the shelves of local retail stores in Dhaka and Bagura.
Scientists found that at the primary producers lever, 72 per cent and 57 per cent milk samples collected were contaminated with coliform and faecal coliform bacteria, respectively and 11 per cent of samples were contaminated with high number of E. coli.
The faecal coliform bacteria is considered as a hygiene indicator and presence of these bacteria in the milk indicates that milk has been contaminated with pathogens or disease producing bacteria or viruses, which can also exist in faeces of warm blooded animals, role of milking animal or the farmers to blame, scientists said.
At the collection points, samples were found to be contaminated with a high number of coliform bacteria and faecal contamination (91 per cent) while more than 40 per cent of samples had a high E. coli count.
At the chilling plants, collected samples were found to be contaminated even at a higher rate than that of collection points.
Samples from all 15 chilling plants distributed in five districts were contaminated with high number of coliform as well as faecal coliform. E. coli was found in samples from all chilling points while 67 per cent of samples were contaminated with high level of E. coli.
Pasteurisation is done to kill pathogenic bacteria to make the milk safe to consume. Both the national and international standards have zero tolerance for faecal coliforms in pasteurised milk.
Speaking about what these findings mean to the consumer, Dr Mohammad Aminul Islam, Associate Scientist and head of the Food Microbiology Laboratory at icddr,b and Principal Investigator of the study said, “Raw or pasteurised milk available in the market are found to be contaminated with disease causing organisms and should not be consumed without thorough boiling.”
The research was funded by CARE Bangladesh through its ‘Strengthening the Dairy Value Chain (SDVC)’ project and was conducted in 18 upazilas of Bogra, Gaibandadha, Nilphamari, Dinajpur, Joypurhat, Rangpur and Sirajgonj.