Consumer demand for healthier, microbiologically safe and stable, higher quality and minimally processed foods has increased in the last decades, promoting the application of non-thermal process technologies. Ultrasound processing is gaining attention because of its potential for improving quality and safety while retaining product flavor, texture, color and nutrient composition. Recently, Alicyclobacillus acidoterrestris has been recognized by manufacturers and processors in the fruit industry as a new type of thermoacidophilic, endospore-forming spoilage bacterium for commercialized fruit juices that can withstand the high temperatures applied in pasteurization process and spoil them producing taint compounds. Based on the above, the present study was undertaken to investigate the separate and combined effect of ultrasound treatment operating at 26 kHz, 90 μm, 200 W for 5, 10, 15 min and heat stress (at 80 °C for 10 min) on the recovery of A. acidoterrestris spores in K broth adjusted to pH = 4.5 with 25% (w/v) citric acid at temperatures between 35 and 45 °C at population and individual spore level. At the population level, statistically significant differences in average lag time of A. acidoterrestris spores from different treatments at 35 and 45 °C have been found. After the applied ultrasound (at 100% Amplitude for 10 min) and heat shock (at 80 °C for 10 min), the average lag time of A. acidoterrestris spores at 35 °C (7.24 ± 0.34 h) and 45 °C (6.38 ± 0.18 h) has been shown to be longer compared to the control at 35 °C (5.68 ± 0.36 h) and at 45 °C (2.87 ± 0.19 h), while for this combination, the maximum specific growth rate was not significantly different from the control samples. Additionally, the findings of this study have shown that λ among individual spores was greatly variable when they were treated by ultrasound (at 100% Amplitude for 10 min) and/or thermal treatment (at 80 °C for 10 min). The application of ultrasound and thermal treatment resulted in a more pronounced effect on median lag phase duration (25.74 h) than the heat shock (11.63 h) and affected both the position and the spread of the λ distributions of A. acidoterrestris spores. This work would help to better assess and optimize the proposed combined treatments, since ultrasound and thermal treatments could work in a synergistic way on delaying the lag time of the tested bacterial spores.

在过去的几十年中，消费者对更健康，微生物学安全，稳定，更高质量和最低限度加工的食品的需求不断增长，促进了非热加工技术的应用。超声波加工因其在保持产品风味，质地，颜色和营养成分的同时提高质量和安全性的潜力而受到关注。最近，酸热脂环酸杆菌已被水果行业的制造商和加工商认可为新型耐热酸，可形成内生孢子的腐败菌，可用于商业化果汁，可承受巴氏灭菌过程中所用的高温并破坏其产生异味化合物的能力。基于以上所述，本研究旨在研究在26 kHz，90μm，200 W下超声处理5、10、15分钟和热应力（在80°C下进行10分钟）时超声处理的单独和组合效果。用25％（w / v调节至pH = 4.5的K肉汤中回收酸曲霉孢子）柠檬酸在35至45°C的温度下（按种群和单个孢子水平）。在种群水平上，已发现在35和45°C下，来自不同处理的酸曲霉孢子平均滞后时间在统计学上有显着差异。施加超声波（在100％振幅下持续10分钟）和热休克（在80°C下持续10分钟）后，嗜酸曲霉孢子的平均滞后时间分别在35°C（7.24±0.34 h）和45°C（在35°C（5.68±0.36 h）和45°C（2.87±0.19 h）的情况下，与对照组相比，6.38±0.18 h的时间更长，而对于这种组合，最大比生长速率并不明显与对照样品不同。此外，这项研究的结果表明，λ超声波（在100％振幅下10分钟）和/或热处理（在80°C下10分钟）处理时，单个孢子之间的差异很大。超声和热处理的应用对中位滞后阶段持续时间（25.74 h）的影响比热冲击（11.63 h）更为显着，并且影响了嗜酸曲霉孢子λ分布的位置和分布。这项工作将有助于更好地评估和优化建议的联合治疗方法，因为超声和热处理可以协同方式延迟被测细菌孢子的滞后时间。