Effect of decontamination on the microbial load, the sensory quality and the nutrient retention of ready-to-eat white cabbage

The effect of different decontamination treatments such as washing with sodium hypochlorite (20 and 200 mg/L), peroxyacetic acid (80 and 250 mg/L), neutral electrolysed oxidising water (4.9 and 31.7 mg/L free chlorine) and contact with 1.55 mg/L chlorine dioxide gas on the microbial and sensory quality, and the nutrient content of fresh-cut white cabbage was studied. Only rinsing with 200 mg/L sodium hypochlorite, peroxyacetic acid or contact with gaseous chlorine dioxide resulted in significantly higher reductions of the total plate count (1.5-2.5 log cfu/g) than the ones achieved by washing with tap water (0.5 log cfu/g). However, those treatments giving the best results from a microbial point of view induced significant changes in the sensory quality. Regarding the effects on nutrient content, the mechanical effects caused by water washing already reduced the vitamin C content by 16-29%. Contrary to washing with neutral electrolysed oxidising water and contact with chlorine dioxide gas, a supplementary decrease of the vitamin C content ranging between 9 and 28% was observed, when peroxyacetic acid or 200 mg/L sodium hypochlorite were used. After the use of peroxyacetic acid or gaseous chlorine dioxide, the phenol content also showed a decreasing trend, although not statistically significant. Apart from the effect of washing with water, the lipophilic nutrients were well retained after a decontamination step except for the alpha-tocopherol content, when peroxyacetic acid was used (-43 to 56%), and for the all-trans-beta-carotene content (-8%) of cabbage in contact with gaseous chlorine dioxide. Because of its potential to reduce the initial microbial load without negative effects on the sensory quality, in combination with its limited effects on nutrient content, a treatment with 80 mg/L peroxyacetic acid is preferable to decontaminate fresh-cut white cabbage.