Bacterial lactic acid fermentation is a biological process wherein rapidly fermentable carbohydrates are metabolised by lactic acid bacteria, with lactic acid as a major product. Lactate is the strongest of the common short-chain fatty acids produced by gastrointestinal bacteria and therefore it tends to reduce residual pH more than other acids. During normal conditions, lactate is rapidly absorbed from the intestine or used as a substrate for lactate-utilising bacteria. However, in cases where lactic acid accumulates in lower intestine due to digestive and absorption disorders in the small-intestine, acidosis occurs. This is analogous to lactic acidosis in ruminants and leads to pH reduction and washout of lactate utilisers. In broiler chickens, such symptoms are observed for example when the birds are suffering from coccidiosis or necrotic enteritis and are often negatively correlated with animal performance.

Lactic acidosis can also occur in the human lower intestine in conditions where normal colonic fermentation is disturbed. It is characterised by significant overgrowth of lactic acid-producing bacteria due to increased delivery of readily metabolised carbohydrates to the colon. As a result, erosion of the colonic mucosa and an increased risk of inflammatory bowel disease may follow. There are several reports of increased colonic lactic acid levels in patients with ulcerative colitis.

Alimetrics has a strong expertise in both microbiological and chemical analyses. By applying state-of-the-art molecular techniques we can accurately monitor the abundance of various lactate-producing and lactate-utilising bacteria from a wide variety of intestinal sample types. In addition, we offer analytical packages for the most prominent short-chain fatty acids produced by intestinal microorganisms.