washed mushrooms and washing mushrooms for 60 s
with 3% H2O2 produced best quality and were superior to ClO2 in
reducing pseudomonad counts .
H2O2 is classified as GRAS (generally recognized as safe) in USA for
use in food products .
As a nonthermal and environment-friendly technology, ultraviolet
C (UV-C) radiation has been approved for use as a disinfectant
for surface treatment of food (US-FDA, 2002) and is used for microbial
reduction in food products. In addition, UV-C can cause
various biochemical responses in fresh produce including induction
of antifungal enzymes and formation of phytoalexin compounds
. Jiang, Jahangir, Jiang, Lu, and Ying (2010) reported
that UV-C could delay softening and enhance antioxidant capacity
in shiitake mushrooms. In addition, irradiation of button mushrooms
with UV-C could inhibit lesion development on the mushroom
surface, reduce Escherichia coli O157:H7 and total aerobic
plate counts on mushroom cap surfaces and result in a significant
increase in vitamin D2 content . Therefore, it has been proposed
that UV-C light be used for sanitizing fresh button mushrooms and
extending shelf-life.
A combination of H2O2 with UV-C, based on the principle of
advanced oxidative process, has been developed with enhanced
efficacy for inactivating bacteriophage on lettuce surfaces . Hadjok, Mittal, and Warriner
(2008) concluded that UV þ H2O2 could reduce the populations
of human pathogens and spoilage bacteria on the surface and those
internalized within fresh lettuce, spinach, broccoli, cauliflower,
onion and tomato without affecting the shelf-life stability. To our
knowledge, none of the studies examined the efficacy of UV-C in
combination with H2O2 on microbial and sensory quality of
mushrooms during cold storage.
The objective of this work was to evaluate the effects of H2O2
combined with UV-C radiation on inactivation of E. coli O157:H7
and the microbial loads on mushrooms during cold storage. In
addition, visual quality, total phenolics and ascorbic acid contents
of mushrooms were examined.