THE EFFECT OF CINNAMON AND GUAR GUM ON BACILLUS CEREUS POPULATION IN MILK

Abstract

Milk was inoculated with Bacillus cereus and the effect of cinnamon and guar gum on B. cereus counts in ultra high-temperature milk was examined by storing samples at 4 and 25C and determining microbial counts as total bacteria by plate count agar at 0, 7, 14 and 28 days. Cinnamon with or without guar gum did not significantly affect B. cereus count at 4C, but it reduced B. cereus counts of milk compared with B. cereus counts of control milk at 25C. Increasing cinnamon concentration from 0.5 to 1% increased antimicrobial effect at the starting of storage but did not affect final B. cereus count. Cinnamon shows antimicrobial activity with their essential oils penetrating through food medium to the microbial cell so the viscosity of food medium caused by stabilizers is a factor that can affect the diffusion of antimicrobial agents through medium to microorganisms and was determined by rotational viscometer. The viscosity of milk with guar gum (0.5%) was found higher than the viscosity of milk that was not including guar gum, but at the end of 28 days the B. cereus counts of milk with guar gum and cinnamon were not higher than the B. cereus counts of milk with cinnamon alone at 25C.