Probiotics are feed and food supple

Probiotics are feed and food supplements that beneficially affect
the host’s health. Strain identity is important in order to link a
strain to a specific health effect and to enable accurate surveillance
and epidemiological studies (Pineiro and Stanton, 2007).
The term ‘‘probiotic’’ includes a large range of microorganisms,
mainly bacteria but also yeasts. Because they can stay alive until
the intestine and provide beneficial effects on the host health, lactic
acid bacteria (LAB), non-lactic acid bacteria and yeasts can be
considered as probiotics. LAB are the most important probiotic
known to have beneficial effects on the human gastro-intestinal
(GI) tract. These bacteria are Gram-positive and usually live in a
non-aerobic environment but they also can support aerobic conditions
(Holzapfel et al., 2001; Anal and Singh, 2007). Bifidobacteria
are also Gram-positive and can grow at a pH range of 4.5–8.5 but
the most important characteristic is the fact that they are strictly
anaerobic (Holzapfel et al., 2001; Anal and Singh, 2007). Other
LAB (e.g. Lactococcus lactis, Enterococcus faecium, etc.) and non-lactic
acid bacteria (e.g. Escherichia coli strain nissle) but also some
yeasts (e.g. Saccharomyces cerevisiae, Saccharomyces boulardii,
etc.) are also considered as probiotics. It has been mentioned that
dead bacteria, products derived from bacteria or end products of
bacterial growth could provide some health benefits. However, because
they are not alive when administrated they cannot be considered
as probiotics (Sanders et al., 2007).