Abstract:
Milk adulteration is a serious issue especially in developing countries where adequate quality
control facilities are less available. The present study was carried out during 2019 to investigate
the quality and the extent of adulteration of raw milk reaching chilling centers belong to Milk
Industries of Lanka Company (MILCO) Private Ltd situated in three Districts (Matara, Galle, and
Hambantota) of Southern Province in Sri Lanka. Raw milk brought by individual farmers and
from milk collecting points were thoroughly mixed at chilling centers and were separately
collected into 250 mL screw capped cleaned dry sample collection bottles. Collected samples
were immediately transported in ice boxes to the laboratory of the Department of Animal
Science, Faculty of Agriculture, University of Ruhuna for analysis. Total 78 milk samples were
analyzed using standard procedures for pH, titratable acidity, specific gravity (SG), composition,
heat/alcohol stability and for the presence of adulterants (ammonium sulfate, cane sugar,
formalin, salt, starch and detergents). Data were analyzed using SPSS (ver. 20). Mean total solids
(TS) and the solid nonfat percentage of the milk from Hambantota district was observed to be
significantly (p<0.05) higher compared to the other two districts. Mean TS and SG of milk from
Matara district was lower than the average values for cow milk. Titratable acidity of milk from
all locations was observed to be normal and within the acceptable level. It was found that
17.95% of milk samples were positive only for the detergents but none of the other adulterants
tested. Milk from Hambantota was found to have the highest percentage of samples failing
alcohol and clot on boiling tests (20 and 15%, respectively), followed by Galle (11.5 and 7.7%)
and Matara (3.1 and 0.0%) districts. Milk adulteration seems to be controlled by application of
proper testing protocol in chilling centers.
