The use of lactic acid bacteria to reduce mercury bioaccessibility

•Use of lactic acid bacteria (LAB) to reduce Hg species bioaccessibility was tested.•All LAB strains reduce bioaccessibility of Hg from standard solution (72-98%).•Significant reductions in Hg bioaccessibility were observed in mushrooms (up to 68%).•No effect of LAB was evidenced on Hg bioaccessibility in seafood samples.•The bioaccessible Hg in fish may be in a chemical form that do not interact with LAB.

Mercury in food is present in either inorganic [Hg(II)] or methylmercury (CH3Hg) form. Intestinal absorption of mercury is influenced by interactions with other food components. The use of dietary components to reduce mercury bioavailability has been previously proposed. The aim of this work is to explore the use of lactic acid bacteria to reduce the amount of mercury solubilized after gastrointestinal digestion and available for absorption (bioaccessibility). Ten strains were tested by addition to aqueous solutions containing Hg(II) or CH3Hg, or to food samples, and submission of the mixtures to gastrointestinal digestion. All of the strains assayed reduce the soluble fraction from standards of mercury species under gastrointestinal digestion conditions (72-98%). However their effectiveness is lower in food, and reductions in bioaccessibility are only observed with mushrooms (⩽68%). It is hypothesized that bioaccessible mercury in seafood forms part of complexes that do not interact with lactic acid bacteria.