Microbial contamination found in pasteurised milk

BFSA probe finds gaping leaks along dairy value chain

Emran Hossain | Published: 00:07, Dec 27,2018


A probe by Bangladesh Food Safety Authority has found gaping leaks along diary value chain causing widespread microbial contamination in cow milk processed for pasteurisation.
The probe samples covering all the registered pasteurised milk producers were collected at three stages of pasteurisation, transportation and retailing for tests at laboratories.
Most of them failed the test, with detection of bacteria, including E Coli, at levels higher than permissible.
Some of the test results came as sheer shock to the members of the probe body, prompting them to undertake immediate inspection of pasteurisation plants.
Conditions at two of the plants based in Kushtia and Pabna were so deplorable that the BFSA inspectors immediately shut all their operations.
Another five companies were cautioned as their conditions were better but not up to the standard. Currently eleven companies are in the business of cow milk pasteurisation.
It has also been found that none of the companies maintain a proper cold chain while supplying pasteurised milk to retailers.
‘It is almost obvious that pasteurised milk stacked on store shelves are contaminated,’ said a member of the BFSA probe body.
He requested anonymity as he was not authorised to disclose the information.
‘Be sure that it is fully boiled before you consume pasteurised milk,’ the member said.
The head of the probe, BFSA member Monzur Morshed Ahmed, told New Age that their findings were submitted to High Court in October.
The probe was done at the order of HC issued in June.
An ICDDRB research revealing in May that three-fourths of pasteurised milk were unsafe for direct consumption prompted the HC move.
‘The HC will decide our next moves,’ said Monzur.
In ideal case pasteurised milk is supposed to be free from dangerous pathogens and safe enough for consumption without cooking.
Pasteurisation is a process in which milk is heated to a certain temperature for a certain period of time to kill disease causing organisms in it.
Former Bangladesh Agricultural University food technology professor Burhan Uddin said that cold chain was central to the pasteurisation technology.
Pasteurisation of milk is not sterilisation of milk, said Burhan.
Pasteurised milk may still contain organisms, but makes sure that the harmful ones are eliminated, he said.
‘If the cold chain was not maintained, organisms still present in the milk turn pathogenic in half to an hour in weather conditions like that of in Bangladesh,’ said Burhan.
Once pasteurised, he said, the milk must be preserved in temperature below 4 degrees Celsius or 39 degrees Fahrenheit.
The BFSA probe, however, reveals that many of the vans companies use for supplying pasteurised milk to retailers lack cooling system.
A member of the probe team said that half of the 48 vans used by Milk Vita, a state-owned milk production company, did not have cooling mechanism.
‘You won’t have to rely much on guessing to get an idea of the condition in private sector,’ said the member.
There were key-points in cities and across the country to which the manufacturers would take their products in vans, said the member.
Distributors would gather at the points and collect the products to deliver it to retailers, he said.
‘The distributors mostly use human-driven three-wheeler vans for completing the delivery job,’ said the member.
One of the most common sights people get about food delivery system in the country is three-wheeler delivery vans carrying pasteurised milk till late in the afternoon in the sweltering summer heat of 32 degrees Celsius, moving slowly through the maddening city traffic.
Stores are unaware about the importance of keeping the cold chain for preserving pasteurised milk, finds the BFSA probe.
‘Cold chain awareness may not be of much help either in areas where power supply is interrupted routinely almost round the year,’ said the BFSA member.
‘We are facing an impossible situation here,’ he said.
Samples collected right off the belt carrying milk packages out of pasteurisation machines at plants tested positive for high concentration of pathogenic bacteria as well.
‘It means those were not properly pasteurised,’ said the BFSA member.
The plants that were shut down lacked technical manpower for pasteurisation.
It was also found at the plants that pasteurisation machines were not cleaned for a long time.
The former BAU professor Burhan Uddin said that pasteurisation was a highly technical task.
There were different methods of pasteurisations and it needed to be validated by the Bangladesh Standards and Testing Institution, he said.
Investigators also needed to know if the machines being used at the moment were validated too, he said.
‘An invalidated thermometer gives wrong reading and thus pasteurisation may remain incomplete,’ said the member.
Countries around the world started making pasteurisation of milk mandatory since the early 20th century as contaminated milk continued to cause widespread deaths.
According to British medical journal about 65,000 people died of tuberculosis contracted through milk consumption between 1912 and 1937 in England and Wales alone.
Milk pasteurisation is mandatory in New York since 1910 as nutrition rich milk is an ideal medium for proliferation of pathogens.
Through the pasteurisation process is killed the pathogens causing tuberculosis, brucellosis, diphtheria, scarlet fever, and Q-fever, among others.
The US centre of disease control says diseases caused by improperly handled raw milk are responsible for three times more hospitalisations than any other food-borne diseases.
The ICDDR,B research had revealed that raw milk samples collected from different points of milk value chain were highly contaminated.
The contamination only increased as the milk moved up the value chain till reaching consumers, suggested the research.
More than two-thirds of commercially processed pasteurised milk samples did not meet standard microbiological limits, according to the research.
As many as 158 of the total 438 samples tested during the research were contaminated with E Coli. Nine per cent of them were pathogenic.
About 13 per cent of the E Coli samples, put to test to measure their capacity of resistance to antibiotic treatment, were resistant to three or more antibiotics, found the research.
About 60 per cent were resistant to at least one antibiotic, it said.
Organisms laboratory tests found present in the samples were Coliform, fecal coliform, E Coli, B Cereus and coagulase positive staphylococci.
Widespread adulteration of milk and milk product in neighbouring India has prompted a WHO advisory stating that failure to contain the situation would see 87 per cent Indian suffering from serious disease like cancer by 2025.

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