Four inoculated strawberries (100±20 g) were randomly selected
and placed into quart-size Ziploc bags (Johnson & Son). To obtain
the initial population of L. monocytogenesorE. coliO157:H7 on
strawberries, 4 inoculated fruits were put into a sterile sampling bag
with 99 mL of BP. After the strawberries were pummeled for 2 min
at 230 rpm in a stomacher, the fruit homogenate was subjected to
the microbiological analysis. The disinfection effect of DW (control), NaOCl solution, and EO water againstL. monocytogenesand
E. coliO157:H7 was determined in whole fruit tissues and on fruit
surfaces only. Studies were also conducted to evaluate the rinsing
effect after sanitizing. Disinfecting agents were added to strawberries in the Ziploc bag with a fruit-to-treatment solution ratio of 1:
3 by weight and contact time of 1, 5, or 10 min at room temperature (22±1
◦
C). After the exposure, strawberries were immediately
removed from the sanitizer, and then immersed in the neutralizing buffer solution (Becton Dickinson Co.) with an equal amount of
sanitizer in another Ziploc bag for 2 min with 100 rpm agitation to
inactivate the bactericidal action of the sanitizers. The treated fruits
were transferred to a sterile sampling bag and mixed with 99 mL of
BP. In the experiment without a neutralization step, treated samples
were drained and placed into a sterile sampling bag with 99 mL of
phosphate buffer. Fruit and BP were homogenized at 230 rpm for
2 min. The tissue homogenates were serially diluted in 9 mL BP and
duplicate samples of 0.1 mL aliquots were spread on the appropriate
agar medium. A 1 mL of neutralizing buffer was also serially diluted
and 0.1 mL aliquots were surface plated in duplicate to enumerate
the viable cells recovered from the surface of the samples