Fig 1.
Analyte profiles of five different wheat flours.
Samples of various wheat flours were analyzed for their analyte profiles. Analytes measured included (A) amino acids, (B) sugars, (C) fatty acids, (D) and minerals.
Fig 2.
STEC survival in different wheat flours during long-term storage.
The following wheat flour types were used: Whole wheat (purple), all-purpose bleached (blue), all-purpose unbleached (yellow), bread (red), and self-rising (green). Three samples of each flour, inoculated with either (A) STEC O121 or (B) STEC O157, were sampled and enumerated. The log ratio of culture levels (logS(t), wherein S(t) = Ni/N0) is plotted against the time. Error represents the mean ± standard deviation of three samples.
Fig 3.
STEC O121 survival in different wheat flours following isothermal treatments.
The following wheat flour types were used: Whole wheat (purple), all-purpose bleached (blue), all-purpose unbleached (yellow), bread (red), and self-rising (green). Two independently inoculated samples of each flour were sampled in duplicate and subjected to isothermal treatments at (A) 60°C, (B) 70°C, (C) 80°C, and (D) 90°C. The log ratio of culture levels (logS(t), wherein S(t) = Ni/N0) is plotted against the time. The length of time at the specified isothermal temperature was determined for each temperature individually. Error represents the mean ± standard deviation of two independent samples with two replicate samplings each (n = 4). Points without error bars indicate only a single sample above the limit of detection. Lines cut off when the culture goes below countable numbers.
Fig 4.
STEC O157 survival in different wheat flours following isothermal treatments.
The following wheat flour types were used: Whole wheat (purple), all-purpose bleached (blue), all-purpose unbleached (yellow), bread (red), and self-rising (green). Two independently inoculated samples of each flour were sampled in duplicate and subjected to isothermal treatment at (A) 60°C, (B) 70°C, (C) 80°C, and (D) 90°C. The log ratio of culture levels (logS(t), wherein S(t) = Ni/N0) is plotted against the time. The length of time at the specified isothermal temperature was determined for each temperature individually. Error represents the mean ± standard deviation of two independent samples with two replicate samplings each (n = 4). Lines cut off when the culture goes below countable numbers.
Table 1.
D-value estimates as calculated by Bayesian first-order isothermal inactivation kinetic model of different STEC-inoculated wheat flours.