Summary

            We hypothesize that by providing ideal enrichment conditions for Lactobacillus helveticus, we can isolate L. helveticus from spoiled milk.  Our primary enrichment conditions included the use of acidic Tomato Juice Agar and the incubation of media at 45ºC. Optimal growth of L. helveticus occurred with a 10^-2 dilution incubated for 24 hours.  The following tests were used to verify the presence of L. helveticus: Gram stain, catalase test, sugar fermentation tubes: lactose, glucose, mannitol, and sucrose.   Results of these tests showed our isolated bacteria to be a gram positive rod, lacking catalase and an endospore. The isolated bacteria did not ferment sucrose and mannitol, variably fermented lactose, and did ferment glucose.  With the exception of the lactose result, the results obtained are consistent with what is characteristic of L. helveticus. Therefore, we are confident that we have successfully isolated Lactobacillus helveticus, an important bacteria in cheese making and with potentially beneficially effects on human health.