Table 3 Common criteria generally considered as essential for the safety of NF/probiotic products (required for both novel food and health claim regulations)
| Â | What | How | Why | Comments and Propositions for improvement | |
|---|---|---|---|---|---|
Survival in GI tract conditions | Resistance to intestinal stress | In vitro Growth curves/Detection in feces after consumption | Resistance to GI tract conditions may favor the beneficial effects | Not valuable for all beneficial effects | |
Development of new protectors/encapsulators | |||||
Bile salt deconjugation | High-performance liquid chromatography | Large amounts of deconjugated bile salts may have undesirable effects on the human host | Evaluation of property in vitro has poor relevance; assessment of bile salt deconjugation in vivo | ||
Mass spectrometry | Â | Â | |||
Preservation of the homeostasis of gut barrier components | Microbiota | Perturbation of commensal consortium | In vitro production of bacteriocins or antibiotics (AB) | Bacteriocins and AB may perturb microbiota. | Development of growth inhibitory references with major commensal bacteria |
AB may interact with a patient’s treatment | |||||
Antibiotics (AB) resistance | In silico *prediction and in vitro antibiogram | AB resistance may be transmitted between bacteria | Development of in vivo assessment (animal model) indicating the microbiota homeostasis (composition and activities) after probiotic consumption | ||
Minimal inhibitory concentration test (MIC) | |||||
Minimal bactericidal concentration test (CMB) | If plasmids are detected: the presence/absence of genes encoding the most common resistance determinants should be characterized | ||||
Presence of plasmids | In silico *prediction or DNA extraction followed by analysis by gel electrophoresis | Plasmids favor the transmission of antibiotic resistance | Requirement to up-date the antibiotic list | ||
Mucus | Mucus degradation | Mucin degradation test (agarose gel or liquid culture) | Excessive mucus degradation may lead to intestinal barrier weakening | The capacity to degrade mucus seems to be a poor criterion to estimate the protective or deleterious effect of bacteria on the intestinal barrier | |
Adhesion and translocation risk | Intestinal/Mucosal adhesion | Test bacterial strain adhesion to epithelial cell line | Mucosal adhesion may interfere with pathogenic microorganisms, stimulate beneficial cellular processes, or favor bacterial translocation | The intestinal/mucosal adhesion capacity can be either a beneficial or a deleterious criterion | |
Intestinal mucosa degradation | Gelatinase activity assay | Mucosal degradation may weaken the intestinal barrier | It could be useful to evaluate in vivo translocation capacities | ||
Hemolytic activity | Blood agar culture | Hemolysis damages red blood cells | Â | ||
Metabolic activities | D-Lactate production | Colorimetric assay | D-Lactate accumulation in blood leads to acidosis | The production of D-lactate should be compared with the amount produced by usual strains (like in yoghurt) | |
Toxin production | Protocol recommended by the European scientific committee of animal nutrition. | Toxic molecules | Establishment of threshold values relevant in humans | ||
Biogenic amine production | Colorimetric assay | Immune responses such as allergic responses | |||
Remote effects | Platelet aggregation | Aggregation test | Risk of thrombosis | Development of ex vivo protocols (explants, organoids) | |
Genotoxicity | Toxicity testing on animals models (chronic and subchronic tests) | Risk of cancer | |||
Allergenicity | Â | Allergic response | |||