• The attachment ability of Salmonella to peanut and almond seeds was evaluated. • Five mutants, each of S . Tennessee and S . Enteritidis, and wildtypes were included. • Mutant cells attached to the seeds at lower levels compared to the parent cells. • Cells of S . Tennessee attached at higher levels on blanched than unblanched peanuts. Attachment is a critical step for bacterial establishment in low-moisture foods and subsequent survival under desiccation conditions. This study assessed the attachment ability of five knock-off mutants, each of S. Tennessee and S . Enteritidis, along with their wildtype parents, to peanut and almond seeds. Sterilized sandy soil (20 g per sample) containing 10 6 (lower level) or 10 7 (higher level) CFU/g of lyophilized cells of wildtype and mutant Salmonella were mixed with sterilized peanut (blanched and unblanched) or almond seeds at room temperature for 1 h with mixing. Seeds were subsequently soaked in 5 ml phosphate-buffered saline (PBS) to release attached Salmonella cells at 4˚C for 0 or 24 h. The percentages of cells in contaminated sandy soil attached to the seeds were determined. The cells of Salmonella mutants had a significantly ( P ≤ 0.05) lower percentage of attachment than those of the wildtypes. On average, more S. Tennessee cells attached to blanched than unblanched peanut seeds, especially at the lower inoculation level. Seed soaking time did not significantly affect the release of Salmonella cells from peanut and almond seeds to PBS. The results of the research are useful for developing novel antimicrobial interventions to control Salmonella establishment in low-moisture foods.
Lee et al. (Sun,) studied this question.