Abstract：
A time-temperature indicator (TTI) system based on the pH-dependent colour change caused by the growth of a Carnobacterium maltaromaticum strain was developed to specifically provide a real-time indication of quality and shelf life of Australian vacuum-packed (VP) lamb throughout cold chains. Each component of the developed TTI system was studied to select an optimal concentration of a chemical chromatic indicator (chlorophenol red, CR; between 0.01 % and 0.30 %) and supplementary glucose (between 0 % and 10 %), and an appropriate C. maltaromaticum strain (among four different strains) in a simple BHI medium. BHI medium containing 0.01 % CR and 1 % added glucose, inoculated with C. maltaromaticum strain 1 were required for development of the TTI system to indicate quality and shelf life of VP lamb. Different inoculum levels of C. maltaromaticum strain 1 (103 to 105 CFU/mL) were also examined at 8 °C for their effects on the TTI response. As expected, higher inoculum levels of C. maltaromaticum led to a shorter endpoint of the TTI system but it was found that a 3 log10 higher inoculum level in the TTI than the expected total viable counts of VP lamb was required to accurately predict VP lamb shelf life by the TTI. To further evaluate the applicability of the TTI system, we evaluated its response at two other temperatures (2 °C and 4 °C) relevant to the storage conditions for VP lamb. The data showed a strong agreement between the observed TTI\'s endpoints and predicted shelf lives of VP lamb. This indicated that the developed TTI has the potential to be developed further for commercial application to provide a real-time, distinct, and accurate indication of Australian VP lamb.
摘要：
开发了一种时间-温度指示器（TTI）系统，该系统基于由苦油肉杆菌菌株的生长引起的pH依赖性颜色变化，以专门提供澳大利亚真空包装（VP）羔羊的质量和保质期的实时指示整个冷链。对开发的TTI系统的每个组件进行了研究，以选择化学色度指示剂（氯酚红，CR;在0.01％至0.30％之间）和补充葡萄糖（在0％至10％之间），和在简单的BHI培养基中的适当的C.maltaromaticum菌株(在四种不同的菌株中)。含有0.01%CR和1%添加葡萄糖的BHI培养基，TTI系统的开发需要接种苦草菌株1，以指示VP羔羊的质量和保质期。还在8°C下检查了不同接种物水平的拟南芥菌株1(103至105CFU/mL)对TTI响应的影响。不出所料,较高的拟南芥接种物水平导致TTI系统的终点较短，但发现TTI中的接种物水平比预期的VP羔羊的总活菌计数高3log10，以准确预测VP羔羊的保质期TTI。为了进一步评估TTI系统的适用性，我们评估了在与VP羔羊的储存条件相关的另外两个温度（2°C和4°C）下的响应。数据显示，观察到的TTI终点与VPlamb的预测保质期之间存在很强的一致性。这表明，开发的TTI有可能进一步开发商业应用，以提供实时，distinct,和澳大利亚VP羔羊的准确指示。
