The origin of off-odours in packaged rucola (Eruca sativa).

Rucola (Eruca sativa) was decontaminated and then reinoculated with selected microorganisms. The produce was then stored in three different atmospheres and at two temperatures. The accumulation of off-odours in the packaging headspace was analysed. A dozen compounds were detected by olfactometry but only dimethyl sulphide and dimethyl disulphide were considered to have a strong or moderate intensity. Thus, they were identified as the substances causing an unpleasant smell inside the bags. Inoculation with microorganisms resulted in higher production of off-odours. Samples inoculated with Pseudomonadaceae&Xanthamonadaceae were particularly potent in producing the two sulphides. The off-odour problem was much more prominent in samples that were kept in a packaging material that did not allow gas exchange resulting in oxygen levels below 1%. Higher levels of sulphides were detected at 8°C than at 4°C.