Influence of antibiotic residues on lactic coagulation of milk

One of the important factors which affect lactic starter cultures activity as well as lack of lactic coagulation in milk is antibiotic residues. Lack of lactic coagulation causes a number of problems such as economic loss in dairy industries when they produce fermented milk products specially cheese and yoghurt. In order to recognize such problem، the present study was undertaken to detect antibiotic residues in milk. The results obtain showed، cow milk which contaminated by ointment in a concentration about 100ppm and the cow under treatment by streptomycin (intramuscular injection) up to 72 hours after injection، no lactic coagulation was observed. Hence، the cow under treatment should be kept separate and the milk drawn should never be mixed with other animals until the antibiotic residues reduce to normal range. Above mentioned parameter have different affects on enzymatic coagulation of milk.