EFFECT OF WASHING WITH CITRIC ACID OR SODIUM HYPOCHLORITE ON THE VISUAL AND MICROBIOLOGICAL QUALITY OF MUSHROOMS ( AGARICUS BISPORUS L.)

The effect of washing with a solution of 10 g/L citric acid or 100 mg/L acidified sodium hypochlorite solution (pH 6.5) on the visual and microbiological quality of whole mushrooms when stored at 3C for up to 13 days was evaluated. The washed mushrooms were compared with water‐washed and untreated mushrooms. The color, bacterial blotch incidence and Pseudomonas counts were determined. Washing with citric acid reduced Pseudomonas counts by 2 log units throughout storage and avoided bacterial blotch during 13 days of storage at 3C, but color deterioration was observed. Washing with sodium hypochlorite hardly reduced Pseudomonas and did not avoid bacterial blotch, and even produced mushroom browning. The effect of the washing treatments depended on the initial condition of the mushrooms used.PRACTICAL APPLICATIONS Hypochlorite has been traditionally used to reduce microbial contamination. However, washing with acidified hypochlorite is not effective in reducing the microbial counts in mushrooms during storage. This treatment does not avoid bacterial blotch and causes color deterioration. Therefore, this washing treatment cannot be recommended in mushrooms. Washing with citric acid has a beneficial effect on reducing microbial counts and extending the shelf life of mushroom. However, it cannot be recommended for washing whole mushrooms because it leads to color deterioration. This treatment could be effective if it is followed by anti‐browning treatment.