Purpose: The main objective of this study, conducted during the 2013 through 2015 harvesting seasons in five regions in Florida, was to evaluate the efficiency of postharvest processing of tomatoes in commercial packinghouses.
Methods: Determination of total aerobic plate count (APC), total coliforms (TC) and generic E. coli (EC) from 840 composite samples (five tomatoes/sample), both before and after processing, were carried out to accomplish this objective. One hundred ml of 0.1% (w/v) sterile peptone water (Thermo Fisher Scientific, Waltham, MA) was added to sterile sample bags, each containing five tomatoes. Each tomato was rubbed for 60 s. One hundred μl of rinsate from all serial dilutions was spread plated onto plate count agar (Thermo Fisher Scientific, Waltham, MA) for enumeration of APC, and onto CHROMagar™ ECC (DRG International, Inc., Mountainside, NJ) for determining TC and EC.
Results: The least square mean (LSM) value of APC for preprocessed samples (6.5 log CFU/tomato) was highly significantly lower (P<0.0001) in postprocessed tomatoes (5.6 log CFU/tomato). The LSM for TC counts were 4.3 and 3.9 log CFU/tomato in preprocessed and postprocessed samples, respectively. Eighty-nine out of 840 (10.6%) and 821 out of 840 (97.7%) samples had TC and EC counts below the detection limit of 1.3 log CFU/tomato. There was no significant difference in the occurrence of EC in preprocessed and postprocessed samples. The APC and TC counts showed highly significant (P<0.0001) seasonal variation.
Significance: Information from this study is suitable for identifying areas in which improvements are necessary to optimize standard postharvest operational procedures to ensure produce safety and subsequently control disease outbreaks.