This study demonstrated the significant, either main or combined, effects of the direction, the instant, and the magnitude of temperature shifts on the induced lag time for germination. Experiments were carried out on synthetic medium at 0.995 aw. Therefore in these conditions the lag time (h) was negligible compared to the shelf-life of bakery products. But the lag time, expressed in percentage, was in the range _12% to 65% of the germination time. Therefore assuming the same range for the lag time for conidia contaminating bakery products (0.91e0.93 aw for example) the effect on the shelf-life can be significant. The effect of the direction of the shift was already mentioned for bacteria Mellefont and Ross (2003),.reported that temperature downshifts induced larger relative lag times, than equivalent upshifts. The same authors also reported the importance of the physiological state of the organisms when shifts are applied.