Probiotics are beneficial microorganisms which provide beneficial metabolic functions and health benefits to the host within the human gastrointestinal (GI) tract. One such microorganism is Bifidobacterium animalis, which is a Gram-positive, non-sporing, and non-motile anaerobic bacteria which can be utilized to treat various human GI diseases but however is quite tricky to grow due to being a strict anaerobic bacterium. The aim of this research is to determine the best co-culture ratio of B. animalis, L. acidophilus, and L. fermentum to help support the growth of B. animalis within aerobic conditions. Preliminary research identified the culture that was being used as well as making a growth curve to determine the growth rate from the slopes of the equation of the trendline for each microbe used. The result of this study showed that within the 5 ratios used being (1:0:0), (1:1:1), (2:1:1), (1:2:1), and (1:1:2) with the microbes being B. animalis, L. acidophilus, and L. fermentum respectively, the co-culture ratio which showed the highest growth rate was 1:2:1, however the amount of living B. animalis that is present within the coculture has not been determined yet. This study has attempted to isolate B. animalis with a few selective media which were mupirocin media, sodium propionatelithium chloride media, and Bifidobacterium media where results showed that the media utilized either inhibited the growth of B. animalis which was seen with the mupirocin media and Bifidobacterium media or did not inhibit the growth of L. acidophilus or L. fermentum being the sodium propionate-lithium chloride media.