The present study indicates that bothL.monocytogenesandE.coli
O157:H7 can survive on strawberries beyond their expected market
shelf life of cold storage at 4±1
◦
C. However, the recovery levels
decreased after the extended storage regardless of the prior treatment. The NaOCl solution and EO water did not have a significantly
superior effect than DW on controlling pathogens during refrigeration storage (P>0.05). Beuchat and Brackett (1991) also noted that
prior treatment with chlorinated water (210 to 280 ppm free chlorine) did not affect the survival ofL. monocytogenesinoculated into
tomatoes during storage at 10
◦
C. We observed a total reduction of
approximately 2.6 and 2.1 log10CFU/g withL. monocytogenesand
E. coliO157:H7, respectively. The results of our study are consistent
with that of Roering and others (1999) who observed that the resistance ofE. coliO157:H7 to the acidic conditions of apple cider (pH
3.3 to 3.5) was much greater thanL. monocytogenesat refrigeration
temperature. Han and others (2004) observed that acid-sensitive
bacteria such asL. monocytogenesmay be injured and inactivated
when exposure to organic acid released from strawberries during
stomaching. This contributed to their observations of lower bacterial recovery. Besides the lethal effect of low pH and cold temperature, studies have also suggested that the dryness on fruit surfaces,
lack of nutrients, and growth of competitive microorganisms may
contribute to a decreased number of viable cells during a long-time
storage (Knudsen and others 2001; Yu and others 2001; Han and
others 2004).