Department of Food Science, Faculty of Food Engineering, State University of Campinas, Campinas, SP, Brazil.
Int J Food Microbiol. 2010 Feb 28;137(2-3):299-302. doi: 10.1016/j.ijfoodmicro.2009.11.029. Epub 2009 Dec 3.
The percentage P (%) of spoiled bottles (n=40) of clarified apple juice due to Byssochlamys fulva, was modeled by using a logistic model: P = P(max)/1 + exp (k(tau-t)) where P(max) (%) the maximum percentage of spoiled bottles, k (h(-1)) a slope parameter and tau (h) the time for P=P(max)/2. Bottles of pasteurized apple juice were inoculated with B. fulva IOC 4518 ascospores for low and high initial loads, 4.8+/-2.3 ascospores/100mL and 19.3+/-4.6 ascospores/100mL respectively and incubated at 21 degrees C and 30 degrees C. P(max) was not significantly different from 100% except for a low initial load at 21 degrees C. Model parameters were estimated with a good accuracy, RMSE in the range 3.89-7.50. Then the model was used to determine the time for 10% bottles spoiled, t(10%). This time was greater at low initial loads, 57.4 and 104 h at 30 and 21 degrees C respectively, than at high initial loads 23.9 and 75.1h at 30 and 21 degrees C respectively. This study demonstrated that even at a very low initial contamination, clarified apple juice can be easily spoiled by B. fulva highlighting the importance of controlling critical control steps of fruit juice processing (i.e., fruit washing, juice filtration and pasteurization).
由于深红红酵母（Byssochlamys fulva）的存在，40 瓶澄清苹果汁中有 P%（%）的瓶数发生变质，采用 logistic 模型对其进行建模：P = P(max)/1 + exp (k(tau-t))，其中 P(max)（%）为变质瓶的最大比例，k（h(-1)）为斜率参数，tau（h）为 P=P(max)/2 时的时间。巴氏杀菌苹果汁的瓶中接种深红红酵母 IOC 4518 的分生孢子，低初始负荷为 4.8+/-2.3 个/100mL，高初始负荷为 19.3+/-4.6 个/100mL，在 21°C 和 30°C 下孵育。除了在 21°C 下低初始负荷时，P(max)没有显著差异，接近 100%。模型参数的估计具有良好的准确性，RMSE 在 3.89-7.50 范围内。然后，使用该模型确定 10%瓶变质的时间，t(10%)。低初始负荷时，在 30°C 和 21°C 下分别为 57.4 和 104 h，高于高初始负荷时，在 30°C 和 21°C 下分别为 23.9 和 75.1h。本研究表明，即使初始污染非常低，澄清苹果汁也很容易被深红红酵母污染，这突出了控制果汁加工关键控制步骤（即水果清洗、果汁过滤和巴氏杀菌）的重要性。
