Influence of Superheated Steam Temperature and Moisture Exchange on the Inactivation of Geobacillus stearothermophilus Spores in Wheat Flour‑Coated Surfaces by Park et. al..
Food and Bioprocess Technology, Springer, 2022
https://doi.org/10.1007/s11947-022-02830-3
Abstract
Sanitation in dry food processing environments is a major challenge for the industry. The influence of superheated steam
(SH) temperatures (125 to 250 °C) on the inactivation of spores on selected coupon surfaces (stainless steel, rubber, and
concrete) coated with wheat flour as a model food soil residue was investigated using a bench scale superheating apparatus.
Wheat flour inoculated with Geobacillus stearothermophilus (7.62 ± 0.12 log CFU/g) coated on the coupon surfaces served
as the model food residue. Among the surfaces tested, temperature of concrete increased faster [time constant (τ) < 89.0
s] than that of stainless steel (τ < 173.6 s). As a consequence, wheat flour coated on concrete dehydrated faster [moisture
diffusivity (Dm) > 1.17 × 10−4 mm2/s] than those on the stainless steel (Dm > 0.76 × 10−4 mm2/s). Hence, Geobacillus
stearothermophilus spores suspended on stainless steel were inactivated faster than that of concrete and rubber (p < 0.05).
The time required for a 5-log reduction at 250 °C were 180s and 240s, on stainless steel and concrete surfaces, respectively.
A mathematical model that considered surface temperature, food residue moisture content, and SH inversion temperature
adequately described spore inactivation during SH treatment.