Safety aspects of probiotic products

Abstract

Probiotics (i.e. ingested living microorganisms) may theoretically be responsible for four types of side effects: systemic infections, deleterious metabolic activities, excessive immune stimulation in susceptible individuals, and gene transfer. Very few cases of adverse events have been reported in humans consuming probiotics, and these are summarized in this paper. I also briefly summarize the three approaches which can be used to assess the safety of a probiotic strain: studies on the intrinsic properties of the strain, studies on its pharmacokinetics, and studies searching for interactions between the strain and the host. Key words: Bifidobacterium, Lactobacillus, probiotics, safety, side effects