A Review of Criteria and Methods for Evaluating the Probiotic Potential of Microorganisms

ABSTRACT

Probiotics are live organisms that, when consumed in sufficient quantities, confer health benefits to the host. There is global interest in probiotics research; many are isolated from diverse niches and identified in numerous ways. The challenge is selecting the precise range of tests and methods to use. Some tests are argued to be outdated, biased and/or irrelevant. Screening guidelines exist, but at times are not strictly followed. In many countries, firm regulations regarding probiotics declaration and use are nonexistent. Consequently, some organisms are presented as probiotics without strong scientific evidence. This review discusses common screening approaches, their relevance, strengths and weaknesses.

Abbreviations: ADP: Adenosine Diphosphate; ATCC: American Type Culture Collection; ATP: Adenosine Triphosphate; BSH: Bile Salt Hydrolase; Caco-2: Cancer coli-2; cFDA-SE: Carboxyfluorescein diacetate succinimidyl ester; CLSI: Clinical and Laboratory Standards Institute; DNA: Deoxyribonucleic acid; EPN: Epinephrine; FAO: Food and Agriculture Organization; FbPA: Fibronectin binding protein A; FDA: Food and Drug Authority; GIT: Gastrointestinal tract; GRAS: Generally Recognized as Safe; HEPES : 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; HT-29: Human colon adenocarcinoma cells; HT-29 MTX: Methotrexate treated human colon adenocarcinoma cells; ICMR-DBT: Indian Council of Medical Research and Department of Biotechnology; IBS: Irritable Bowel Syndrome; ICR: Inherited Cataract Rat; LAB: Lactic Acid Bacteria; MFI: Mean Fluorescence Intensity; MIC: Minimum Inhibitory Concentration; mRNA: Messenger Ribonucleic Acid; MRS: de Man Rogosa Sharpe; NCCB: Netherlands Culture Collection of Bacteria; OD: Optical Density; PBS: Phosphate Buffered Saline; PGE: Prostaglandin; RBC: Red Blood Cells; SHIME: Simulator of the Human Intestinal Microbial Ecosystem; SDS-PAGE: Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis; TLC: Thin-Layer Chromatography; TRAP-6: Thrombin Receptor Activator Peptide-6; WHO: World Health Organization

KEYWORDS:

• Probiotics
• screening methods
• health benefits
• safety

Acknowledgments

Thanks to Dr. Ueli von Ah for permission to use the illustration on stomach-intestinal passage simulation using a bioreactor. Thanks to Dr. Gurudayal Singh Toteja as well for permission to use the illustration on guidelines for evaluation of candidate probiotics strains developed by the Indian Council of Medical Research (ICMR) and Department of Biotechnology (DBT). We acknowledge the Food Technology and Business Incubation Center (FTBIC), Makerere University, Kampala for its contribution to this work.