Thermal inactivation of non-proteolytic Clostridium botulinum spores in chilled plant-based foods

To support innovation in the dynamic plant-based foods sector, a study was conducted to set fit for purpose and risk-based alternative thermal processing conditions to the usually used safe harbour heat treatment of 90 °C - 10 min that ensures food safety of extended shelf life refrigerated products. To do so, inactivation data were collected to determine the thermal resistance properties (D- and z-values) of non-proteolytic Clostridium botulinum Type E spores (reference strain NCTC 8266) then build and validate specific inactivation models for two plant-based products: Konjac-based Seafood Analogue (Product 1) and Canola-based Eggs Analogue (Product 2) with desired sensorial properties not compatible with the application of the classical heat treatment of 90 °C - 10 min.

D-values were determined at five temperatures ranging from 78 °C to 86 °C for each matrix to build the model and additional data were collected at 75 °C and 80 °C to validate the model. D_ref80°C-values were estimated at 1.90 and 0.80 min and z-values at 6.12 °C and 6.84 °C respectively for products 1 and 2. Simulations were performed to estimate the time required to reach the required Performance Objective (PO) of 6 log reductions to ensure food safety at different temperatures for each product. The targeted PO could be reached in both products with lower temperatures and shorter times compared to the safe harbor. Results showed that the inactivation of non-proteolytic C. botulinum Type E spores was faster in product 2 compared to product 1. The developed and validated models, together with the proposed methodology can be used to support food industries in collecting specific data to justify setting fit for purpose heat treatments ensuring food safety with regards to the control of non-proteolytic C. botulinum type E spores without compromising on the desired sensorial properties such as those required for some plant-based products.