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Objective: To assess the effect of natural concentrations of LPS in cow’s milk on E.coli 0111:B4 in UHT milk.
Design: Experimental study.
Procedure: Different concentrations of E.coli (101-103-107 cuf/ml) were inoculated into the UHT milk which contained active LPS to study the effect of the system on the microorganism. Two concentrations of LP (10 and 30 ppm) which are the naturally accrued of this enzyme in raw milk were prepared and added to the UHT milk together with each of the microorganism concentrations mentioned above with 0.25 mM of thiocy,anate and 0.25 mM of hydrogen peroxide, control was prepared using UHT milk with I08 cfu/ml of microorganism. All the samples and control were stored at 4°C and 25°C and tested at 0, 1,2,7 and 14 days intervals. For each sample and control two repetition were considered.
Statistical analysis: Two ways analysis of variance.
Results: The micro organism in the samples showed the same growth trendes as in the controls. The data obtained in his study, shows that the LPS has no considerable antibacterial effect on E.coli 0111 :B4. J. Fac. Vet. Med. Univ. Tehran. 57, 2: 77-81,, 2002.