Control of Aeromonas on minimally processed vegetables by decontamination with lactic acid, chlorinated water, or thyme essential oil solution

Aeromonas is an opportunistic pathogen, which, although in low numbers, may be present on minimally processed vegetables. Although the intrinsic and extrinsic factors of minimally processed prepacked vegetable mixes are not inhibitory to the growth of Aeromonas species, multiplication to high numbers during processing and storage of naturally contaminated grated carrots, mixed lettuce, and chopped bell peppers was not observed. Aeromonas was shown to be resistant towards chlorination of water, but was susceptible to 1% and 2% lactic acid and 0.5% and 1.0% thyme essential oil treatment, although the latter provoked adverse sensory properties when applied for decontamination of chopped bell peppers. Integration of a decontamination step with 2% lactic acid in the processing line of grated carrots was shown to have the potential to control the overall microbial quality of the grated carrots and was particularly effective towards Aeromonas.