Sodium nitrite is used as an additive in the production of meat products, however, nitrite is carcinogenic due to the synthesis of nitrosamines. Fermented sausages are meat products which are produced by microbiological, biochemical, physical, and sensory changes in the meat, under certain temperatures and relative humidity conditions. These physicochemical changes result in a longer shelf life. The lactic acid bacteria have the ability to inhibit the growth of pathogenic and spoilage bacteria, reduce nitrate, improve the color, taste, and texture of fermented sausages. In this study, the effect of coating type, fermentation time, temperature, and relative humidity on fermented sausages was investigated in order to increase the shelf life of the product. Nine log CFU/g of Lactobacillus plantarum PTCC 1896 and Lactobacillus fermentum PTCC 1744 was used for chicken meat fermentation. The sausage dough was then filled into cellulosic coatings, lined polyethylene molds, and lidless polyethylene molds and then fermented at 7 °C. After examining the physical, chemical, and microbial properties of the fermented sausages on the 0, 1 st , 4 th , and 7 th days of fermentation, the results showed that the pH after 4 days of fermentation was the most suitable for preventing microbial spoilage. Cellulose coating resulted in higher pH level, and hardness, while cohesiveness decreased. The total count of mold and yeast in the lidless sample increased despite the higher lightness, yellowness, springiness, and cohesiveness compared to the cellulose coated sample. The lowest pH and the most suitable moisture content was related to sausage with mold and lid coating. Also, the highest lightness, yellowness, springiness, and cohesiveness with a good degree of hardness, chewiness, and gumminess was observed. The reduction of coliform count in the sausage with mold and lid coating was more than the sausage coated by cellulose. During the storage period, the fermented sausage (optimized sample) was subjected to different conditions (relative humidity: 99% and 35%, temperature: 15 and 20 °C). The results of experiments after 0, 5 th , 10 th , and 15 th days of storage showed that at 99% relative humidity, the lightness, hardness, gumminess, and chewiness of fermented sausage increased. Also, the lowest count of molds and yeasts and the highest count of coliform were observed. By decreasing relative humidity, the redness, yellowness, and the lactic acid bacteria count increased. In addition, the coliform count reached zero. Moreover, by increasing storage temperature, an increase in redness, and pH level, and a decrease in mold and yeast count was observed. Also, by increasing storage temperature at 99% relative humidity, the yellowness increased but the hardness, gumminess, and chewiness decreased. In contrast, by the increasing temperature at lower relative humidity, all the mentioned characteristics remained constant. In the early days of storage, lightness, hardness, gumminess, and lactic acid bacteria count were higher and the coliforms count was lower. Over time, more redness, yellowness, and coliforms count were observed, but springiness, cohesiveness, and chewiness decreased. According to our results, the use of Lactobacillus plantarum and Lactobacillus fermentum for fermentation of sausage (for 4 days at 7 °C) with further storage in the mold with lid coatings (5 days at 20 °C and relative humidity of 35%), can be a good alternative for the production of the nitrite-free products Keywords : Fermented sausages, Nitrite substitutes, Lactobacillus Plantarum , Lactobacillus fermentum