Ali Ghorbani Ranjbary - Young Researchers and Elite Club, Kazerun Branch, Islamic Azad University, Kazerun, Iran.
Mostafa Rostampour - Young Researchers and Elite Club, Kazerun Branch, Islamic Azad University, Kazerun, Iran.
Mohammad Javad sabahi goraghani - Farhangian university Pardis of kerman, Khajeh nasiraldin toosi, Kerman, Iran.
Sara varzandian - Departement of Clinical Science, School of Veterinary Medicine, Kazerun Branch, Islamic Azad University, Kazerun, Iran.

The objective of this study ware to investigate the effects of different doses of Origanum vulgare on the growth of Lactobacillus casei and Lactobacillus paracasei (separated from Iranian dairy products) in milk produced at one step. The product was then examined in terms of pH, acidity and microbe countingduring incubator setting period. In the milk samples with Lactobacillus casei, the control sample reached acidity level more quickly and in the milk samples with Lactobacillus paracasei, the sample containing %1 Origanum vulgare reached acidity level earlier than other samples. In the milk samples with eitherLactobacillus casei or Lactobacillus paracasei, it was observed that during refrigeration the controlsample had the most duration. The bioability of probiotic bacteria was measured by direct counting method. Duration of the product permanence was determined within 21 days. Upon examination of the results, it was revealed that the increased concentration of Origanum vulgare had a positive effect on the growth of the probiotic bacteria, Lactobacillus casei and Lactobacillus paracasei in probiotic milk.

Probiotic, Lactobacillus casei, Lactobacillus paracasei, Origanum vulgare, milk