Bacillus cereus is a major foodborne bacterial pathogen able to survive a large number of physical-chemical stresses. B. cereus encounters different pH and redox potential (E-h7) levels during its passage through the gastrointestinal tract. Analysis of the combined influence of pH and redox stresses on B. cereus F4430/73 physiology found that B. cereus F4430/73 growth at pH 7.0 at 37 degrees C had strong reducing capacities, with a total change of 315 mV from an initial redox value of +214 +17 mV. The combination of low E-h7 and low pH led to a drastic reduction of growth parameters compared to oxidative E-h7 and neutral pH. Metabolic analysis showed that low pH significantly modifies glucose fermentative metabolism, with changes including decreased production of acid metabolite (acetate, lactate, formate) and increased production of 2,3-butanediol. Low E-h7 slightly enhanced the acid-tolerance response of B. cereus whereas low pH pre-adaptation led to thermal stress cross-protection. These results highlight new mechanisms that bring fresh insight into B. cereus pH and redox stress adaptations.