Champagne C P, Raymond Y, Gagnon R
Food Research and Development Centre, Agriculture and Agri-Food Canada, 3600 Casavant, St. Hyacinthe, QC, Canada J2S 8E3.
J Food Sci. 2008 Jun;73(5):M221-6. doi: 10.1111/j.1750-3841.2008.00775.x.
Lactobacillus rhamnosus R0011 was inoculated in an apple-pear-raspberry juice blend at 4.5 x 10(9) CFU/250 mL portion, and viability was followed during storage in conditions simulating consumer use. Study parameters were age of the juice (2 or 4 wk), sampling size (one to three 250-mL portions), incubation temperature (between 2 and 7 degrees C), and atmosphere (aerobic compared with anaerobic). Dependent variables were pH, dissolved oxygen (DO) level, and viable count. The DO level in the unopened PETE commercial bottles decreased from 10% to 3% over a 5-wk storage period at 7 degrees C. In shaken and opened bottles, DO increased to 15% during the 1st week of storage, irrespective of sampling size. However, agitation of bottles having more that 250 mL of headspace initially increased DO readings to 30% of maximum, but the DO level subsequently dropped to 15% during the 1-wk storage period between samplings. The presence of L. rhamnosus R0011 did not affect the DO data. The pH varied between 3.6 and 3.9, and was not influenced by L. rhamnosus R0011. However, the pH increased on average by 0.1 unit following multiple agitations and samplings. When the juices remained unopened in the PETE bottles, the viable population gradually dropped by 75% over 5 wk of storage at 7 degrees C, while in opened bottles reduction were only between 20% and 40%. Viability losses under anaerobic conditions were twice as high at 7 degrees C than at 4 degrees C. Data show that consumers can expect good viability of L. rhamnosus R0011 over a few weeks of storage in a refrigerator, even if the bottles have been opened and cells are exposed to oxygen.
将鼠李糖乳杆菌R0011以4.5×10⁹ CFU/250 mL的接种量接种到苹果 - 梨 - 树莓混合汁中，并在模拟消费者使用的储存条件下跟踪其活力。研究参数包括果汁的储存时间（2周或4周）、取样量（1至3个250 mL的部分）、孵育温度（2至7摄氏度）和气氛（需氧与厌氧）。因变量为pH值、溶解氧（DO）水平和活菌计数。在7摄氏度下储存5周期间，未开封的PETE商业瓶中的DO水平从10%降至3%。在摇晃并打开的瓶子中，无论取样量如何，储存第1周时DO都会增加到15%。然而，初始顶空超过250 mL的瓶子摇晃后，DO读数最初会增加到最大值的30%，但在两次取样之间的1周储存期内，DO水平随后会降至15%。鼠李糖乳杆菌R0011的存在不影响DO数据。pH值在3.6至3.9之间变化，不受鼠李糖乳杆菌R0011影响。然而，多次摇晃和取样后，pH值平均增加0.1个单位。当果汁在PETE瓶中未开封时，在7摄氏度下储存5周期间，活菌数量逐渐下降75%，而在开封瓶中减少仅在20%至40%之间。在7摄氏度下，厌氧条件下的活力损失是4摄氏度下的两倍。数据表明，即使瓶子已打开且细胞暴露于氧气中，消费者在冰箱中储存几周后仍可预期鼠李糖乳杆菌R0011具有良好的活力。
