Introduction:-
Freshness of milk can be retained for long now, scientists
from 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.
The kit also would help to ensure the time period of consuming milk before it turns too sour with the help of Smartphone app.
Milk has been one aming the most
consumed food in daily life, so its safety is a prime issue of concern. It is
highly perishable and prone to action of enzymes and microorganisms inherently
present in it. Although pasteurization, freezing and preservation using
addictives are widely used to prevent spoilage, perishability of milk is still
a concern.
Kit working process
A milk enzyme, alkaline phosphate 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.
So the kit uses an ordinary filter to prepare the detector. The
filter paper which is cut into small pieces is impregnated with chemical probes
that preferentially react with Alkaline phosphates, which is an indicator of
the quality of the milk. When the filter paper impregnated with probes come in
contact with milk, its colours changes.
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 presence
of Alkaline Phosphatase could be
detected but the amount of it in milk could also be measured.
The team has prepared a kit
attached to a 2 cm square transplant cellulose acetate film. The probe is then
covered with another cellulose acetate film. Colour reaction takes place when
milk is injected through tiny hole in the cover and smart phones can be used to
get the results. It takes just about 15 minutes to detect raw milk from pasteurized
one.
The kit could come handy in
milk bars, large kitchens and at milk collection centers where freshness of milk
is concern. It can find other applications too. Since Alp is also tested in various
body fluids, the kit can also be utilized in clinics. Fabrication in the laboratory
at present costs around Rs. 80 to Rs. 125 per kit and could come down when mass
manufactured.
