MedicalResearch.com Interview with: Maria L Marco, PhD Associate Professor Department of Food Science & Technology Davis, CA  95616 Medical Research: What is the background for this study? What are the main findings? Dr. Marco: Probiotics encompass certain strains of bacteria and yeast that when administered alive and in sufficient amounts can confer specific health benefits. Probiotics are increasingly added to foods, beverages, and intestinal supplements for delivery to the digestive tract. (Fermented) dairy products are currently the most popular food carriers for probiotic strains in clinical studies and commercial products. Although microorganisms generally respond quickly and adapt to their surrounding environments (e.g. in foods), the importance of the carrier format on probiotic function in vivo has yet to be systematically and mechanistically investigated. To address this need, we performed a couple studies in rodents to (i) examine whether probiotic Lactobacillus casei produces different proteins during low temperature (refrigeration) incubation in milk and (ii) measure whether incubation in milk is required for L. casei protection against inflammation. We found by shot-gun proteomics that L. casei does adapt for growth and survival in milk by producing a variety of (extra)cellular proteins, even at low-temperatures used to store dairy products prior to consumption. Such exposure of L. casei to milk was also essential for reducing the severity of disease in a mouse model of Ulcerative Colitis (UC), an inflammatory bowel disease characterized by continuous inflammation in the large intestine. Consuming milk alone also provided some protection against weight loss and intestinal inflammation in the Ulcerative Colitis mouse model but was not as effective as L. casei and milk in combination. Lastly, the importance of dairy for L. casei in preventing Ulcerative Colitis was confirmed by our findings that L. casei mutants lacking the capacity to synthesize proteins which are selectively produced during low-temperature incubation in milk were also impaired in preventing inflammatory responses in the intestine. (more…)