Changes in microbial population and quality of microgreens treated with different sanitizers and packaging films

The effects of different sanitizers on the quality and microbial populations of 'Tah Tasai' Chinese cabbage (Brassica campestris var. narinosa) microgreens were evaluated. Samples were washed in tap water (TW), 100 mL center dot L-1 chlorinated water (Cl), 0.25% (w/v) each of citric and ascorbic acid mixed solution (CA + AS) as well as 0.5% (w/v) citric acid solution followed by 50% (v/v) ethanol spray (CA + E) and were packaged either in 35 mu m polyethylene (PE) or polypropylene (PP) bag and stored at 5A degrees C for up to 9 days. The decline of O-2 partial pressure of the packaged headspace and hue angle values were similar in both films. However, the CO2 partial pressure of the packaged headspace and the electrical conductivity were substantially higher in PP packaged samples than that in PE. Off-odor scores were also higher in PP film packaged samples compared to that of PE. CA + E and CA + AS treatments showed lower off-odor scale in both films. Although, visual quality scores showed similar trends at the beginning of storage, CA + E and CA + AS treated samples exhibited better quality on day 7. Samples washed in Cl showed lower microbial count numbers on washing day. However, CA + E treatment exhibited either the lowest or equivalent count numbers in both total aerobic counts and coliforms count to that of Cl until the end of storage. Considering environmental safety, our results suggest that CA + E treatment could be a useful replacement for Cl for the washing of microgreens and PE film would provide more benefits than PP for packaging microgreens.