We prepared a model food emulsion with a microfluidizer incorporating the oxidation-sensitive dye, BODIPY 665/676, which we used earlier for studying lipid oxidation in food emulsions . BODIPY 665/676 shifts its emission wavelength from red to green upon reaction with lipid peroxyl radicals. As the dye has so far only been used at room temperature, its applicability for monitoring oxidation at cryogenic conditions (77 K) is currently unknown. After performing cryo-sample preparation and placing the samples on the cryo-FM platform, the fresh and oxidized emulsions were illuminated at 638 nm with 14 W/cm 2 and 520 nm with 40 W/cm 2 , respectively, to detect non-oxidized and oxidized lipid droplets at 77 K. First, we measured the non-induced samples without dilution to check the appearance of fluorescence from BODIPY 665/676. In non-diluted emulsions, the packing of droplets is too dense to distinguish individual droplets (Fig. &). However, we could see a general decrease in red fluorescence (excitation at 638 nm) and an increase in green fluorescence (excitation at 520 nm) of BODIPY 665/676 in oxidized emulsions at cryogenic temperatures. To observe the effect in individual droplets, we prepared tenfold diluted samples using the acetate buffer. Under the same laser excitation conditions, we could detect the BODIPY 665/676 signals in individual droplets with non-oxidized (ex 638 nm) and oxidized (ex 520 nm) channels in the fresh (Fig. ) and oxidized emulsions (Fig. ). The data show that the shifted emission wavelength of BODIPY 665/676 upon oxidation can be measured not only at room temperature but also at cryogenic temperature. We note that oil droplets larger than the thickness of the embedding vitrified water layer will become oblate which leads, in some cases, to elongated droplets being visible.