Running title:LACTIC ACID BACTERIA IN CHEESES Academy Section: ANIMAL SCIENCE

The profi le of polyunsaturated fatty acids in cheeses obtained through fermentation by lactic acid bacteria Lactobacillus helveticus and Streptococcus thermophilus were evaluated. The milk used to make the cheeses came from cows fed with fl axseed oil and annato. The cheeses presented microbiological and physicchemical quality with in the standards established by the legislation for Staphylococci and Listeria. With maturation, there was a reduction in the coliform values for both treatments. Regarding the counts of lactic acid bacteria, these remained viable until the 30 day of maturation and the proteolytic bacteria decreased. For antioxidant capacity, the treatment containing the combination of the strains obtained high ABTS values. There was no signifi cant difference between the treatments with respect to the color of the samples. For texture, there was a signifi cant difference for the parameters cohesion and elasticity. No increase in CLA content was observed in the form of its two main isomers, however, the levels of polyunsaturated fatty acids were increased four-fold when compared to milk . The inclusion of the evaluated bacteria was effective because it promoted the development of a product with benefi cial characteristics to the consumer.