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1.64 ± 0.19C

4.07 ± 0.37 AB

a Log reduction = mean cell population of untreated inoculated control (duplicate samples) minus mean cell population following washing treatment (duplicate samples). Means with no letter in common are significantly different at p < 0.05. b Mean populations of untreated inoculated control samples.

c Sanova (acidified sodium chlorite) solution was prepared according to the manufacturer's specifications.

d The pH of the chlorine solution was adjusted to 6.5 using concentrated hydrochloric acid.

a Log reduction = mean cell population of untreated inoculated control (duplicate samples) minus mean cell population following washing treatment (duplicate samples). Means with no letter in common are significantly different at p < 0.05. b Mean populations of untreated inoculated control samples.

c Sanova (acidified sodium chlorite) solution was prepared according to the manufacturer's specifications.

d The pH of the chlorine solution was adjusted to 6.5 using concentrated hydrochloric acid.

for surface pasteurization include apples, melons, mangoes, lemons, oranges, cucumbers, pears, tomatoes, and alfalfa seeds.

Immersion of apples in hot water or sanitizing solutions (60° C for

2 minutes) resulted in >4 log CFU/g reductions in Escherichia coli O157:H7 populations inoculated on the skin surface (Table 21.1). However, these treatments were not effective in inactivating cells inoculated in inaccessible sites (stem and calyx) of apples (Table 21.2 and Table 21.3) [3,4]. Fleischman et al. [14] reported similar results for surface pasteurization of apples using water at 95°C for up to 60 seconds. Hot water immersion of apples can result in heat damage resulting in browning of the skin at temperatures above 60°C and softening of the subsurface flesh above 70 to 80°C [7,15].

Reductions in Salmonella Poona populations on cantaloupe surfaces were >5logCFU/cm2 following commercial-scale hot water immersion at 76°C for

3 minutes (Table 21.4) [2]. Also, this hot water commercial-scale treatment maintained the fresh quality and increased the shelf life of this commodity. The use of laboratory-scale hot water or heated hydrogen peroxide treatments (70 or 97°C for 1 minute) to inactivate salmonella cells on cantaloupe rind surface resulted in fresh-cut product with enhanced microbiological qualities [16] and extended shelf life [17]. Hot water immersion (70°C for 2 minutes or 80° C for 1 minute) was shown to be effective in reducing populations of E. coli O157:H7 on orange surfaces [18]. Also, hot water (>57°C for 5 minutes) immersion was effective in reducing populations of S. Stanley on alfalfa seeds [19].

Hot water treatment of a variety of fruits and vegetables greatly improves their microbiological quality and shelf life, while maintaining their sensory qualities. Over-processing of produce, however, can significantly reduce seed germination and cause thermal injury to apples and to juice extracted from

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