L., Santiago de Compostela, Spain). The areas of the broad and narrow components and the line width at half-height of each component were measured by using MestRenova 7. Effective spin–spin relaxation time (T2*) values were obtained using Eq. (1). equation(1) T2*s=1π×v1/2Hzwhere T2* represents the effective spin–spin relaxation time and v1/2 represents the line width at half-height. Significant
differences in water mobility (T2*) at different water activities and for different protein configurations were analyzed by ANOVA using the General Linear Model procedure with Tukey’s test at p < 0.05 (IBM SPSS Statistics for Windows, Version 21.0, click here IBM Corp. Armonk, NY). Water mobility has units of milliseconds (ms). Four Salmonella
serovars previously involved in outbreaks in dry foods were used in this study: Salmonella Typhimurium (peanut), Salmonella Tennessee (peanut), Salmonella Agona (dry cereal) and Salmonella Montevideo (pistachios and others). The cultures were stored in cryovials containing beads suspended in phosphate buffered saline, glycerol and peptone (Cryobank, Copan Diagnostics Inc., CA) and kept at − 80 °C. They were prepared for use by Onalespib consecutive culturing in 9 ml of Tryptic Soy Broth (TSB, Becton, Dickinson and Company, Sparks, MD) at 37 °C for 24 h. Following the second culture, a final transfer of 3 ml to 225 ml of TSB was made, followed by incubation for 24 h at 37 °C. Cells from the final culture were collected by
centrifugation (3363 g, 30 min), the supernatant fluid was removed, and the pellet was re-suspended in 2 ml of 1% bacto-peptone (Becton, Dickinson and Company, Sparks, MD). The cell suspension was then dried in a vacuum desiccator over anhydrous calcium sulfate for a minimum of three days to obtain aw levels below 0.1. The dried cells were pooled and manually crushed into a powder. The dried inoculum (0.05 g) was mixed with 0.95 g of Astemizole moisture equilibrated test protein powder to provide a 1 g sample. This inoculation method led to starting concentrations of 109 CFU/g. Re-equilibration of samples to the target aw was not necessary when using this procedure. Inoculated and control samples were packaged in retort pouches under vacuum to minimize moisture transfer to head space during survival studies. Samples were placed into standard retort pouches (Stock America, Inc., Grafton, WI). Retort pouches were then placed in FoodSaver Quart Bags, and the FoodSaver equipment (FoodSaver Silver, model FSGSSL0300-000, Sunbeam Products, Inc., Boca Raton, FL) was used for pulling a vacuum and sealing. After initial sealing of the FoodSaver bag, a second seal was applied to the retort pouch using an impulse sealer. The vacuum-sealed inoculated samples were stored at different temperatures (21 ± 0.6 °C, 36 ± 0.3 °C, 50 ± 0.5 °C, 60 ± 0.5 °C, 70 ± 0.5 °C and 80 ± 0.5 °C).