Microbial estimation using real-time monitoring of vegetable wash water quality parameters

The real-time effectiveness of washing fresh-cut produce is hard to evaluate because it is impossible to rapidly measure the bacteria levels in the produce and wash water during a continuous washing step. This study aimed to investigate the correlation between microbial levels (total aerobic bacteria [TAB] and coliforms) and water quality parameters (turbidity, color, salinity, and temperature) during the processing of salted Chinese cabbages. Results showed that wash water and cabbage samples were contaminated with TAB and coliforms but not Escherichia coli. Turbidity, as a measure of the wash water quality, had a wide measurement range (0.48–43.48 NTU). There was a very high positive correlation between the TAB levels in all four washing tanks and turbidity (r = 0.98). The error between actual and estimated TAB levels, based on turbidity, was within 8 %. These results suggest that real-time monitoring of turbidity can be applied to the water supply control system to maintain the cleaning effect of salted Chinese cabbages. •No E. coli were found in any wash water or Chinese cabbage samples.•TAB and coliforms were detected in wash water and cabbage samples.•TAB levels in washing tanks highly positively correlate with turbidity.•The error between actual and estimated TAB count based on turbidity was 0.1–7.8 %.