title: 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.
authors.affiliation: Department of Food Science and Technology, University of Georgia, Griffin, GA 30223-1797, USA. lbeuchat@uga.edu
authors.forename: Larry R
authors.initials: LR
authors.lastname: Beuchat
authors.forename: David A
authors.initials: DA
authors.lastname: Mann
authors.forename: Walid Q
authors.initials: WQ
authors.lastname: Alali
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D031325:Carya / Q000382:microbiology*; D002713:Chlorine / Q000494:pharmacology; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004305:Dose-Response Relationship, Drug; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control*; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D006801:Humans; D019344:Lactic Acid / Q000494:pharmacology; D007982:Levulinic Acids / Q000494:pharmacology; D012475:Salmonella / Q000187:drug effects* / Q000254:growth & development; D012478:Salmonella Food Poisoning / Q000517:prevention & control; D012499:Sanitation; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000890:Anti-Infective Agents; D007982:Levulinic Acids; D019344:Lactic Acid; D012967:Sodium Dodecyl Sulfate; D002713:Chlorine; C032246:levulinic acid