Enzymatic browning is a major factor contributing to quality loss in foods and beverages. Browning usually impairs the sensory properties of products due to changes in colour and flavour, as well as softening (Martinez and Whitaker, 1995),and usually occurs in Agaricus bisporus mushrooms during handling, processing and storage after harvest (Bernas et al.,2007; Jaworska et al., 2008; Tano et al., 1999). Mushroom browning is usually associated with oxidase activity and
ubiquitous microflora.