The present invention discloses a method to carry out in vivo testing of antioxidant status of foods using genetically modified yeast cells (mutant yeast cells) which expresses human proteins and helps to quantify actual anti-oxidant status of foods. The novel microbes express Prx1 and Prx 2: human proteins i.e. peroxiredoxin which are good oxidant sensors and change shape on intracellular and extracellular stress exposure. For in vivo testing, anti-oxidants extracted from foods are added to media at defined concentrations (1.2%) and the microbe allowed to grow. Thereafter, expression of human proteins expressed by the mutant yeast is quantified using immune-blotting. Higher levels of dimer form of PRX1 and PRX2 indicate good anti-oxidant activity of the test compound while low levels of PRX1 and PRX2 indicate poor anti-oxidant activity.
