Abstract: In order to determine the effect of garlic in Cemen on reduction of Escherichia coli O157:H7, Cemen with different garlic levels (0, 7.5, 10.0, 15.0, 20.0 and 25%) were prepared. Each batch of Cemen was contaminated with E. coli O157:H7 (107 cfu g-1) and stored at 4°C for 60 days and 20°C for 60 days in sterile glass jars. E. coli O157:H7 counts and pH were determined at various stages of storage. It was determined that both garlic levels and storage temperatures had significant effect on E. coli O157:H7 count. E. coli O157:H7 in Cemen that was stored at 4°C were slowly inhibited than that stored at 20°C. During storage at 4°C, E. coli O157:H7 count dropped to below detectable level (< 100 cfu g-1) at 30 days in Cemen containing 25% garlic while at 45th days in Cemens containing 10, 15 and 20% garlic. At 20°C, it dropped below detectable level (< 100 cfu g-1) on the 10th days in Cemens containing 10, 15, 20 and 25% garlic. Investigating with immunomagnetic seperation (IMS), it was determined that the samples with below detectable level (< 100 cfu g-1), contained E. coli O157:H7.