Purpose: The purpose of this study was to evaluate chlorinated water, organic acids (lactic, levulinic, peracetic) with and without sodium dodecyl sulfate (SDS), and water extracts of inedible pecan components for their efficacy in killing Salmonella on in-shell pecans and pecan nutmeats.
Methods: In-shell pecans and nutmeats (USDA medium pieces) were dip inoculated in a five-serotype suspension of Salmonella, dried to ca. 3.7% moisture, and stored at 4 °C for 3 - 6 weeks. Samples were immersed in chlorinated water (200, 400, 1,000 µg/ml), lactic acid (0.5, 1, 2%) and levulinic acid (0.5, 1, 2%) with and without 0.05% SDS, a peracetic acid-based sanitizer (40 µg/ml), and water extracts of pecan hulls, shells, and pith at 21 °C for up to 20 min.
Results: Treatment of in-shell pecans with chlorine (400 µg/ml) for 20 min reduced Salmonella by 2.6 log CFU/g, whereas treatments with 2% lactic acid plus SDS and 2% levulinic acid plus SDS reduced the pathogen by 3.7 and 3.4 log CFU/g, respectively; treatment with the peracetic acid-based sanitizer resulted in a 2.4-log CFU/g reduction. Lactic and levulinic acids without SDS were less effective than acids with SDS. Reductions on nutmeat pieces were less than 1.1 log CFU/g, regardless of acid or acid/SDS concentration or treatment time. Compared to acid treatments, treatment with water extracts of inedible nut components was less effective in killing Salmonella.
Significance: None of the sanitizers evaluated was effective in killing high numbers of Salmonella (> 3.7 log CFU/g) on in-shell pecans and nutmeats. The importance of preventing contamination cannot be overemphasized.