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A paper sensor that can detect freshness of milk

Topics covered:

  1. Science and Technology- developments and their applications and effects in everyday life Achievements of Indians in science & technology; indigenization of technology and developing new technology.
  2. Indigenization of technology and developing new technology.

 

A paper sensor that can detect freshness of milk

 

What to study?

For Prelims and Mains: Alkaline Phosphatase and about the new methodology to test the freshness of milk.

 

Context: Scientists at Indian Institute of Technology, Guwahati, have developed a simple paper kit that can test freshness of milk and tell how well it has been pasteurized. Aided with a smart phone app, the kit can help ensure that milk is consumed before it turns too sour.

 

Background:

Milk being widely consumed food, its safety is of prime concern to consumers. More so because it is highly perishable and prone to action of enzymes and microorganisms inherently present in it. Although pasteurization, freezing and preservation using additives are widely used to prevent spoilage, perishability of milk is still a concern.

 

The new method- how it works?

  • A milk enzyme, Alkaline Phosphatase or ALP, is considered an indicator of milk quality because its presence even after pasteurization indicates presence of microbes that may not have been rendered inactive with pasteurization.
  • Researchers used ordinary filter paper to prepare the detector. The filter paper was cut into small discs and impregnated with chemical probes that preferentially react with ALP. The ‘probes’ used are antibodies that specifically bind to ALP. When ALP comes into contact with the probe, it turns white paper disc into a coloured one.
  • The colour change on paper discs is then photographed by a smartphone camera and images processed to obtain corresponding colour values. These values are then compared with standard data stored in the phone. Thus not only the presence of ALP could be detected but the amount of it in milk could also be measured.

 

Sources: the hindu business line.