Lab4 and Lab4b are lactic acid bacteria (LAB) and bifidobacteria that have been isolated from the gut microbiota of healthy humans and then screened for appropriate probiotic characteristics, ranging from resistance to stomach and bile acids, to robust capability for large-scale in-vitro cultivation and commercialisation.

The Lab4 consortium combines four strains of lactic acid bacteria and bifidobacteria isolated from human gut microbiota – two strains of Lactobacillus acidophilus, one Bifidobacterium animalis subsp. lactis and a Bifidobacterium bifidum.

The Lab4b consortium also combines four strains of lactic acid bacteria and bifidobacteria that have been specifically designated to reflect the gut of newborn babies and infants. This combination contains the same Bifidobacterium animalis subsp. lactis and Bifidobacterium bifidum as the Lab4 consortium, but contains Lactobacillus salivarius and Lactobacillus paracasei instead of the two Lactobacillus acidophilus strains.

Since their inception, the Lab4 and Lab4b consortia have been the subject of more than 10 major human clinical trials as well as over 100 basic and mechanistic scientific investigations. Most of this work has been published in peer-reviewed journals.

The Lab4 consortium of probiotic bacteria has been incorporated into many popular brands of probiotic and has benefited thousands of people for over 15 years. It is one of the most studied groups of probiotic cultures in the world.

Background to Lab4 and Lab4b

The isolation and selection of bacterial strains suitable for inclusion in human probiotic products involved a two-stage screening program of organisms based on a range of characteristics.

The program of testing was based on microbiological principles coupled with in vitro screening techniques and first-hand knowledge of the efficacy of probiotics within the animal husbandry sector.

Selection was based on a two-phase system to ‘weed out’ strains at various stages through the selection process to enable the most appropriate strains to be selected.

Two of the key requirements for the strains were durability and ‘competitivity’ – to ensure good growth and the ability to survive when faced with opportunistic pathogens.