Highlights
• One-step growth simulation of B. thermosphacta in beef was performed using HSI.
• Three methods for simulating B. thermosphacta growth by HSI were compared.
• Model Ⅰ using PLSR was best to simulate B. thermosphacta growth (R2 = 0.971).
• HSI and plate count methods were highly consistent in growth simulation.
Abstract
In this work, one-step growth models using hyperspectral imaging (HSI) (400–1000 nm) were successfully developed in order to estimate the microbial loads, minimum growth temperature (Tmin) and maximum specific growth rate (μmax) of Brochothrix thermosphacta in chilled beef at isothermal temperatures (4–25 ℃). Three different methods were compared for model development, particularly using (Model Ⅰ) the predicted microbial loads from partial least squares regression of the whole spectral variables; (Model Ⅱ) the selected spectral variables related to microbial loads; and (Model Ⅲ) the first principal scores of HSI spectra by principal component analysis. Consequently, Model Ⅰ showed the best ability to predict the microbial loads of B. thermosphacta, with the coefficient of determination (Rv2) and root mean square error in internal validation (RMSEV) of 0.921 and 0.498 (lg (CFU/g)). The Tmin (–12.32 ℃) and μmax can be well estimated with R2 and root mean square error (RMSE) of 0.971 and 0.276 (lg (CFU/g)), respectively. The upward trend of μmax with temperature was similar to that of the plate count method. HSI technique thus can be used as a simple method for one-step growth simulation of B. thermosphacta in chilled beef during storage.