A new test carried out on 10% of milk samples indicated the small presence of pathogens despite going through the pasteurisation process, according to a report to be published in Food Microbiology.

Dr Cath Rees and PBD Biotech co-founder Dr Ben Swift have developed the Actiphage test at the University of Nottingham in order to detect the presence of live mycobacteria in milk.

The phage-based test is said to have detected viable mycobacterium avium subspecies paratuberculosis (MAP) in 10.3% of the 386 samples of retail purchased pasteurised milk.

MAP can lead to Johne’s disease, a chronic wasting disease found in cattle and other ruminants, which affects animal health and significantly impacts the dairy industry economy.

The bacterium has also been associated in the development of the Crohn’s disease, as mycobacteria were identified in the bowel tissue of patients.

During the tests, around two-thirds of the MAP-positive samples contained just 1-2 detectable MAP cells per 50ml, while a further 1.1% contained more than 10 detectable MAP cells per 50ml.

"Dr Cath Rees and I discovered that using the Actiphage test mycobacteria cells could be rapidly detected in multiple sample types at very high sensitivity and specificity."

Dr Swift said: “Dr Cath Rees and I discovered that using the Actiphage test mycobacteria cells could be rapidly detected in multiple sample types, such as blood and milk, at very high sensitivity and specificity.

“Additionally, the phage-based diagnostic can distinguish between viable and non-viable organisms. These research findings emphasise the important role that Actiphage can play within food manufacturing as part of quality assurance programmes, helping to continue building consumer confidence in our already-high standards.”

The Actiphage test, which has the ability to deliver results in hours, rather than weeks, will enable producers and processors to more efficiently and effectively assess milk as part of the production line.

PBD Biotech CEO Dr Berwyn Clarke said: “We now have a new research tool at our fingertips that can rapidly detect the presence of MAP in all tissue and fluid at very high sensitivity, providing a real opportunity to improve our understanding of this mycobacteria and its associated diseases.”

The phage-based test has also been successfully used to detect viable MAP in raw milk, powdered infant formula, cheese products, and in the blood of infected animals.