In spite of large amounts of production of high quality date fruits in Iran with high exports value, lots of this valuable product (ca. 22%) go to waste mostly due to microbial and other kind of contaminations that occurs because of unsuitable harvesting, traortation, packing and storage. However, this situation has caused an undertone in the world marketing of this product. In general, the cost of modified atmosphere packaging and irradiation of dates is high and on the other hand toxicity of fumigants like methyl bromide and sensitiveness of dates to heat and heat resistance of its spoiling microorganisms; have limited application of these methods to preserve dates. Therefore studying the other ways of disinfecting the fruits, such as cold pasteurization, is of great importance. In this research, the effect of using food preservatives in their allowed amounts, at different temperature along with vacuum packaging on shelf life of date fruits were investigated. Mazafaty and Stamaran were chosen as wet and semidry dates and then a w , pH, acidity and microbial load of fresh dates has been measured; the samples were then divided to 700 grams masses and each was washed and treated with one of the preservative solutio dimethyldicarbonate, dehydroacetic acid, parahydroxy abenzoic acid, sorbic acid and salicylic acid that were prepared in two permissible concentrations. Then they were dried up to original moisture content and packed. Samples with no preservative, and without washing samples, were also packed using vacuum and ordinary packaging. Each treatment was prepared in two similar packages; one was stored in refrigerator and the other stored at room temperature for up to 6 months. Acidity pH and sensory evaluation of samples at one month intervals and microbial assessment at the end of storing period indicated that the effects of temperature, preservatives, concentrations and vacuum packaging were all significant. The most effective preservatives were dimethydicarbonate, dehydroacetic acid and parahydroxy benzoic acid respectively, while vacuum packaging had an effect similar to the least concentration of preservatives. Sensory evaluation revealed that these preservatives had acceptable effect regarding odor and taste. Results also indicated that treatments except vacuum packaging had least effect on texture and appearance of products.
