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ABSTRACT: This work compared bacterial gastrointestinal (GI) resistance of commercial probiotic products (capsules, fermented milk and powder). To simulate GI transit, the probiotic products were subjected to gastric fluid for 120 min then to intestinal fluid for 180 min. Gastric and intestinal fluids were prepared according to United States Pharmacopeia protocols. Bacterial enumeration was compared before and after the GI transit to evaluate the protective effect of the vehicle or the food matrix. Bacteria of the four probiotic capsules covered with an enteric coating had a higher survival rate (<1 log^sub 10^ CFU reduction) than uncoated. Eight encapsulated but non enteric coated probiotic products showed limited GI resistance (between 1 and 5 log^sub 10^ CFU reduction) while five products showed no GI survival. For probiotic fermented milk, two products demonstrated excellent or good protective property (<1 log^sub 10^ CFU reduction) while the other four showed no resistance. Only one of six powdered probiotic strains had excellent GI survival. This study demonstrated that GI survival varies from one probiotic product to another. It reiterates the importance of manufacturing probiotic strains using the appropriate vehicle for the bacteria to reach its site of action and produce the expected beneficial effects.
KEY WORDS: Acid Tolerance, Bile Salts, Gastrointestinal, Probiotic
INTRODUCTION
Probiotics are defined as «live microorganisms which, when administered in adequate amounts, confer a health benefit on the host» (Araya et al. 2002). A good probiotic strain should preferably be of human origin, possess a generally recognized as safe (GRAS) status, the capacity to survive through the gastrointestinal (GI) tract and colonize the gut (Ronka et al. 2003). A wide range of probiotics ready for consumption are currently available on the market. However, the efficacy of commercially available probiotic products differs a lot, since their properties and characteristics are different from a probiotic strain to another. In most cases, marketing has preceded scientific control (De Angelis et al. 2007). In fact, the GI survival of several strains of probiotics has not been supported by scientific evidence. In order for the bacteria to exert their beneficial effects on the host, they must be able to survive and reach the GI tract in sufficient numbers, at least 106-107 CFU/g (Bosnea et al. 2009). The ability of a probiotic...