Compositional Quality and Potential Gastrointestinal Behavior of Probiotic Products Commercialized in Italy

Abstract

Recent guidelines indicate that oral probiotics, living microorganisms able to confer a health benefit on the host, should be safe for human consumption, when administered in a sufficient amount, and resist acid and bile to exert their beneficial effects (e.g., metabolic, immunomodulatory, anti-inflammatory, competitive). This study evaluated quantitative and qualitative aspects and the viability in simulated gastric and intestinal juices of commercial probiotic formulations available in Italy. Plate counting and MALDI-TOF mass spectrometry were used to enumerate and identify the contained organisms. In vitro studies with two artificial gastric juices and pancreatin-bile salt solution were performed to gain information on the gastric tolerance and bile resistance of the probiotic formulations. Most preparations satisfied the requirements for probiotics and no contaminants were found. Acid resistance and viability in bile were extremely variable depending on the composition of the formulations in terms of contained species and strains. In conclusion, this study indicates good microbiological quality but striking differences in the behavior in the presence of acids and bile for probiotic formulations marketed in Italy.

Keywords: MALDI-TOF; acid resistance; bile tolerance; gastric juice; intestinal fluid; microbial identification; probiotics.

Figure 1

Viability of probiotic formulations in the ASTM-simulated gastric fluid. Microbial counts were carried out at 0, 30, 60, and 120 min and expressed as log CFU/unit dose of each product. ^aP < 0.05, ^bP < 0.01, and ^cP < 0.001.

Figure 2

Viability of probiotic formulations in the U.S. Pharmacopeia simulated gastric fluid. Microbial counts were carried out at 0, 30, 60, and 120 min and expressed as log CFU/unit dose of each product. ^aP < 0.05, ^bP < 0.01, and ^cP < 0.001.

Figure 3

Behavior of probiotic formulations in simulated intestinal juice. Microbial counts were carried out at 0, 30, 60, 120, 240, and 360 min and expressed as log CFU/unit dose of each product. ^aP < 0.05, ^bP < 0.01, and ^cP < 0.001.