Study the ability of some gram positive bacillus species isolated from powdered infant milk to produce toxin

Abstract

Forty samples of different types of powdered infant milk had been collected including (celia 1-2 , biomil 1-2 , lery 1-2 , dialak 1-2 , albadee 2 ,nido 2 , kikos 2 , nictalia 1-2 , cerelak ). Some of the milk cans were opened directly at the beginning of test while others had been opened three days or more before testing. The results showed that Bacillus species were isolated and identified at different rates as Bacillus cereus has the highest rate (12.5%) then B.circulance and B. laterosporous at (5%) for each of them respectively, while B.megaterium was isolated at a rate of (2.5%). The ability of the isolated Bacillus species to produce enterotoxin was detected by the use of Rapid and delayed permeability test for the detection of the heat stable enterotoxin and the results were recorded by the appearance of blue non necrotic lesions after injection of the rabbit with the cell free culture supernated (CFCS) and Lysate supernatant (LS) of the isolated Bacillus species, and for the detection of heat labile enterotoxin, the paw oedema test was also used , the increase in thickness of fore and hind arms appeared. The ability of the Bacillus species to produce the enzyme lecithinase and lyse red blood cells were also studied and the results revealed that only Bacillus cereus produce the enzyme lecithinase. in addition all the isolates showed positive hemolytic activity.