Chrysanthi Champidou ^1* Mariem Ellouze ¹ Nabila Haddad ² Jeanne-Marie Membré ²

• ¹ Nestlé Research Center, Lausanne, Switzerland
• ² INRA UMR1014 Sécurité des Aliments et Microbiologie (SECALIM), Nantes, Pays de la Loire, France

Our study aims to assess the thermal inactivation of non-proteolytic type B Clostridium botulinum spores in a plant-based fish and to evaluate the potential of alternative heat treatments at temperatures below the safe harbor guidelines established for vacuum-packed chilled products of extended durability, First, the heat resistance of the spore suspension was determined using capillary tubes in potassium phosphate buffer at 80 °C. The D80 value was estimated to be 0.7 – 0.8 min. Then, inactivation was studied in a plant-based fish alternative using “thermal cells equipment”. Inactivation kinetics were obtained at four temperatures: 78, 81, 84 and 85 °C, in duplicates. A secondary model describing log10D values versus temperatures was fitted to the dataset. The model parameters ZT and log10Dref (log10D at Tref 82 °C) were estimated to be 8.02 ± 0.46°C and 0.32 ± 0.02, respectively. Model validation was done first with additional data collected at three different temperatures (79.1, 82.5, 87.5°C) and second with literature data. The time required to deliver 6 log reduction in the plant-based food matrix was predicted at temperatures within the range 80 – 90°C. The recommended processing for vacuum-packed chilled products, 90°C for 10 min, was evaluated. We demonstrated that the recommended processing is approximately five times more than the time required for 6 log reduction of non-proteolytic C. botulinum in the plant-based fish alternative, indicating a substantial margin of safety. Our findings highlight the importance of conducting product-specific studies for the evaluation of thermal processing and the potential of process optimization for certain product categories.