Evaluation of Sanitizers for Inactivating Salmonella on In-Shell Pecans and Pecan Nutmeats

Abstract

Chlorine, organic acids, and water extracts of inedible pecan components were tested for effectiveness in killing Salmonella on pecans. In-shell pecans and nutmeats (U.S. Department of Agriculture medium pieces) were immersion inoculated with a mixture of five Salmonella serotypes, dried to 3.7% moisture, and stored at 4°C for 3 to 6 weeks. In-shell nuts were immersed in chlorinated water (200, 400, and 1,000 μg/ml), lactic acid (0.5, 1, and 2%), and levulinic acid (0.5, 1, and 2%) with and without 0.05% sodium dodecyl sulfate (SDS), and a mixed peroxyacid sanitizer (Tsunami 200, 40 μg/ml) for up to 20 min at 21°C. The rate of reduction of free chlorine in conditioning water decreased as the ratio of in-shell nuts/water was increased. The rate of reduction was more rapid when nuts were not precleaned before treatment. The initial population of Salmonella on in-shell nuts (5.9 to 6.3 log CFU/g) was reduced by 2.8 log CFU/g after treating with chlorinated water (1,000 μg/ml). Treatment with 2% lactic acid plus SDS or 2% levulinic acid plus SDS reduced the pathogen by 3.7 and 3.4 log CFU/g, respectively. Lactic and levulinic acids (2%) without SDS were less effective (3.3- and 2.1-log CFU/g reductions, respectively) than acids with SDS. Treatment with Tsunami 200 resulted in a 2.4-log CFU/g reduction. In-shell nuts and nutmeats were immersed in water extracts of ground pecan shucks (hulls), shells, a mixture of shells and pith, and pith. The general order of lethality of extracts to Salmonella was shuck < shell-pith ≤ shell ≤ pith < chlorine (400 μg/ml) and shuck < shell ≤ pith = shell-pith < chlorine (400 μg/ml). Results emphasize the importance of removing soil and dust on in-shell pecans before conditioning in chlorinated water and the need for sanitizers with increased effectiveness in killing Salmonella on pecans.

A simple, rapid, cost-effective and sensitive method for detection of Salmonella in environmental and pecan samples

“…This developed method can deliver rapid and cost‐effective results than the conventional cultural methods although a lower detection limit of 1 CFU/50 g of in‐shell pecans has been reported by enrichment (Beuchat et al . ).…”

MoWa: A Disinfectant for Hospital Surfaces Contaminated With Methicillin-Resistant Staphylococcus aureus (MRSA) and Other Nosocomial Pathogens

“…The temperature should not represent a factor whether MoWa is utilized in hospital environments where the ambient temperature should be around 20°C but certainly not below 10°C. A similar formulation of LA and SDS has been used overall to disinfect bacteria contaminating pecans ( Beuchat et al., 2012 ; Beuchat et al., 2013 ), cantaloupes ( Webb et al., 2013 ), or beef cheek meat ( Schmidt et al., 2014 ) and from food slicers ( Chen et al., 2014 ). Besides environmental contamination, LA/SDS removed biofilms made by oral streptococci ( Wang et al., 2012 ).…”

“…The efficacy was similarly observed in pure cultures, or when strains were spiked on different surfaces or food items ( Zhao et al., 2011 ; Chen et al., 2014 ). A similar formulation of LA- and SDS-disinfected bacteria from produce such as pecans ( Beuchat et al., 2012 ; Beuchat et al., 2013 ), cantaloupes ( Webb et al., 2013 ), or those contaminating beef cheek meat ( Schmidt et al., 2014 ) and eradicated bacteria from food slicers ( Chen et al., 2014 ). However, the same LA/SDS solution was ineffective to eradicate parasites, such as Cryptosporidium parvum and Encephalitozoon intestinalis ( Ortega et al., 2011 ).…”

Effects of sanitizing treatments with atmospheric cold plasma, SDS and lactic acid on verotoxin-producing Escherichia coli and Listeria monocytogenes in red chicory (radicchio)

“…In this respect, the use of a surfactant might increase the sanitation efficacy of ACP by improving the washing effect. Some studies have reported that combinations of surfactants, such as Sodium Dodecyl Sulphate (SDS), with organic acids have synergistic effect (Beuchat, Mann, & Alali, 2012;Zhao, Zhao, & Doyle, 2009). Besides the antimicrobial property by lowering pH, Lactic Acid (LA) is a permeabilizer of the Gram-negative bacterial outer membrane and showed a strong sensitizing effect to SDS in E. coli and Salmonella Typhimurium (Alakomi, Skyttä, Saarela, & Helander, 2005).…”