The present work aimed at studying the cross contamination of apples by Salmonella during the processing of
commercial fresh apples and its survival capacity on apple at room temperature. For the first study, the typical
process of fresh apples was simulated at laboratory scale in which an apple that was artificially contaminated
by Salmonella at different concentration levels (8, 6 and 5 log cfu/apple) was introduced in one batch and processed
including a simulated transport/washing step and drying step using sponges to simulate the porousmaterial
used in the industry. Results indicated that at 8 log cfu/apple, 50% fresh apples were contaminated after
processing, with all analysed environmental samples being positive for the pathogen, consisting of washing
water and sponges. However, at lower inoculumlevels (5–6 log cfu/apple) no cross contamination was detected
in apples, and only environmental samples showed contamination by Salmonella after processing including both
water and sponges. Experiments on the survival of Salmonella on apple showed that the pathogen was capable to
survive for 12 days, only showing a significant drop at the end of the experiment. Finally, two-class attribute
sampling plans were assessed as tool to detect Salmonella in different contamination scenarios in fresh apple.
This analysis indicated that with the highest inoculum level, a total of 16 apples would be needed to reach 95%
of detecting Salmonella (i.e. lot rejection). In turn, when low levels were assessed (5–6 log cfu/apple), a large
number of apples (n= 1021) would have to be sampled to obtain the same confidence level (95%). If the environment
is sampled (i.e. water and sponges), a lower number of samples would be needed to detect the pathogen.
However, the feasibility of environmental sampling has not been assessed from a practical point of view.
Overall, the results in this study evidenced that cross contamination by Salmonella might occur during processing
of fresh apples and subsequently, the pathogen might survive for a noticeable period of time.
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