Before and After: Evaluation of Microbial and Organic Loads in Produce Handling and Packing Operations with Diverse Cleaning and Sanitizing Procedures

Inadequate cleaning and/or sanitation (C/S) of food contact surfaces (FCSs) has been frequently reported during Produce Safety Rule inspections; however, limited data are available evaluating the effectiveness of C/S processes in produce operations. Different C/S practices were evaluated in four fresh produce operations for their efficacy in reducing microbial and organic loads on various FCSs. Microbial (aerobic plate counts; APC) and organic (ATP) loads were quantified during production, after cleaning, and after sanitizing, if applicable. Operations included: a berry packinghouse (BerryPK; wet cleaning), a blueberry harvest contractor (BerryHC; cleaning + sanitizing, C+S), and two mixed vegetable packinghouses (MixedV1; C+S, and MixedV2; rinsing + sanitizing, R+S). Following wet cleaning, significant reductions in APCs (p < 0.05) were seen on high-density polyethylene (HDPE) storage trays (n = 50) in BerryPK (3.1 +/- 0.9 to 2.5 +/- 0.7 log CFU/100 cm(2)). In BerryHC, a greater reduction in APCs was seen on HDPE harvest buckets (n = 25) following C+S (3.8 +/- 0.5 to 1.1 +/- 0.4 log CFU/100 cm(2)), compared to wet cleaning only in BerryPK. Stainless steel and conveyor belt FCSs (n = 16) in MixedV1 were sampled, and a significant reduction in APCs (p < 0.05) was observed when comparing in-use (4.8 +/- 1.3 log CFU/100 cm(2)) to post-C+S (3.9 +/- 0.7 log CFU/100 cm(2)). When similar FCSs (n = 17) were sampled in MixedV2, R+S also led to significant reduction in APCs (3.3 +/- 0.6 to 1.9 +/- 0.6 log CFU/100 cm(2)) (p < 0.05). ATP testing in fresh produce settings yielded inconsistent results, with no correlation between organic and bacterial loads detected during production (R-2 = 0.00) across four operations, and weak correlations observed after cleaning (R-2 = 0.18) and after sanitation (R-2 = 0.33). The results from this study provide the foundational basis for future research on practical and effective C/S methods tailored to the produce industry.