Abstract The effect of food matrix rheology and fat content on thermal inactivation of Listeria monocytogenes in the Shaka agitated retort (final retort temperatures of 59, 64, and 69 °C) was investigated using four fish-based artificial food model systems: low-viscosity liquid (liquid), high-viscosity liquid (xanthan), and emulsions containing 10% and 20% fat (emulsion 10% and emulsion 20%). Model system rheology, quantified by the consistency index K and the flow behaviour index n, influenced the thermal load to which the systems were exposed during treatments. Thermal loads followed the order liquid ≥ emulsion 10% ≥ emulsion 20% ≥ xanthan, a trend which was also valid for the sublethal injury induced to the cells. Log reductions followed the order liquid ≥ emulsion 10% ≥ xanthan ≥ emulsion 20%, indicating a protective effect of an increased fat content, not related to heat transfer differences. Between approximately 59 and 62 °C, the temperature range over which the largest portion of the inactivation was achieved, the maximum specific inactivation rate kmax followed the same trend as the log reductions. Overall, the effect of food matrix rheology on inactivation efficacy could be linked to heat transfer dynamics, while the effect of fat content was more complex.

中文翻译：

---

Shaka 搅拌式往复罐中单核细胞增生李斯特菌的热灭活：食物基质流变学和脂肪含量的影响

摘要 使用四种基于鱼的人工食物模型系统研究了食物基质流变学和脂肪含量对 Shaka 搅拌式脱水缸（最终脱水缸温度为 59、64 和 69 °C）中单核细胞增生李斯特菌热灭活的影响：低粘度液体（liquid）、高粘度液体（黄原胶）和含10%和20%脂肪的乳剂（乳剂10%和乳剂20%）。由一致性指数 K 和流动行为指数 n 量化的模型系统流变学影响了系统在处理过程中所承受的热负荷。热负荷遵循液体≥乳液 10% ≥ 乳液 20% ≥ 黄原胶的顺序，这一趋势也适用于对细胞造成的亚致死损伤。对数减少的顺序是液体 ≥ 乳液 10% ≥ 黄原胶 ≥ 乳液 20%，表明增加脂肪含量的保护作用，与传热差异无关。在大约 59 至 62 °C（实现最大部分失活的温度范围）之间，最大比失活率 kmax 遵循与对数减少相同的趋势。总体而言，食品基质流变学对灭活功效的影响可能与传热动力学有关，而脂肪含量的影响则更为复杂。