Department of Animal Production and Food Science, Veterinary Faculty, Universidad de Zaragoza, Miguel Servet 177, 50013 Zaragoza, Spain.
Int J Food Microbiol. 2012 Sep 17;159(1):9-16. doi: 10.1016/j.ijfoodmicro.2012.07.020. Epub 2012 Jul 28.
This work approaches the possibility of combining mild heat treatments with citrus fruit essential oils (EOs) to improve the effectiveness of heat treatments and thus to reduce treatment intensity. Concentrations between 10 and 200 μL/L of lemon, mandarin, or orange EO were tested at 54 °C for 10 min in laboratory media, determining that 200 μL/L of each EO was necessary to achieve a 5 log(10) reduction of the initial Escherichia coli O157:H7 concentration. A relationship could be established between sublethally injured cells after the heat treatment and inactivated cells after the combined process. In apple juice, the synergism in the inactivation of E. coli O157:H7 when adding 200 μL/L of lemon EO might suppose a reduction in the treatment temperature (of 4.5 °C) or in the treatment time (by 5.7 times) within the range of temperature assayed (54-60 °C). Addition of 75 μL/L of lemon EO was determined to achieve the same synergistic effect of the combined treatment when the initial inoculum was reduced from 3×10(7) to 3×10(4) CFU/mL. Since the addition of lemon EO did not decrease the hedonic acceptability of apple juice, the proposed combined treatment could be further studied and optimized for the production of new minimally processed juices.
本研究探讨了将温和热处理与柑橘类水果精油（EO）结合使用以提高热处理效果，从而降低处理强度的可能性。在实验室培养基中，将柠檬、橘子或甜橙 EO 的浓度分别在 10-200 μL/L 之间，在 54°C 下处理 10 分钟，结果表明，每种 EO 的浓度为 200 μL/L 时，可实现大肠杆菌 O157:H7 初始浓度 5 log(10)的减少。可以建立热处理后亚致死损伤细胞与联合处理后失活细胞之间的关系。在苹果汁中，添加 200 μL/L 柠檬 EO 对大肠杆菌 O157:H7 的协同灭活作用可能意味着在测试温度范围内（54-60°C），处理温度（降低 4.5°C）或处理时间（缩短 5.7 倍）可以缩短。当初始接种量从 3×10(7)减少到 3×10(4)CFU/mL 时，确定添加 75 μL/L 柠檬 EO 可达到联合处理的协同效果。由于添加柠檬 EO 不会降低苹果汁的感官可接受性，因此可以进一步研究和优化这种联合处理方法，以生产新型的低加工果汁。
