Surveillance of milk adulteration and its influence on physico-chemical characteristics of milk in Hyderabad, Pakistan

Abstract

Present study was carried out to evaluate the common adultrants practiced in market milk at the vicinity of Hyderabad city. In first experiment, a total of 100 unprocesed milk samples (five from each retailer sale points) were collected and examined during the summer season. Market milk was mainly adulterated with water, formalin, cane sugar (CS), skimmed milk powder (SMP), starch and sodium chloride.The water was common adulterants found to be in all the milk samples (100%), followed by formalin (34%), CS (24%), starch (13%), SMP (08%) and sodium chloride (05%). In second experiment, the recovered adultrants (viz., water, starch, SMP, CS, formalin) was used as treatment to record their effects on the physico-chmical charcateristics of normal milk. Significant influence of extraneous water (10 and 20%) among the treatment was observed on physico-chemical characteristics of milk. Decrease in specific gravity (1.027±0.0003 and 1.024±0.001 respectively) and increase in freezing point(-0.462±0.01 and-0.399±0.010C, respectively) was recorded against their corresponding controls (1.030±0.001 and-0.525±0.010C, respectively) by the addition of extrenous water in milk. Addition of 10% water did not show any significant influence (p> 0.05) on pH value of milk (6.68±0.03), while 20% water had remarkable effect (p<0.05) on it (6.72±0.02) compared to that of whole milk (6.64±0.02). comparable reduction (p<0.05) in TS (total solid) content (13.34±0.28 and 11.15±0.44%) as compared to control milk (15.54±0.35) was observed. Protein, fat and lactose contents were also influenced (p<0.05) by addition of extraneous water to control milk. Addition of 1 and 2% each of starch, SMP and CS to normal milk did not show (p> 0.05) any significant influence on pH values and fat contents of milk, except addition of 2% CS that affected the pH (p<0.05). These results indicate alarming state of milk adulteration in Hyderabad city. As these adultrants significantlty affected the physico-chemical characteristics of milk like specific gravity, total solids content, protein and lactose content of milk.