Research Unit Food Microbiology and Food Preservation, Department of Food Technology, Safety and Health, Member of Food2Know, Faculty of Bioscience Engineering, Ghent University, Belgium.
Research Unit Food Microbiology and Food Preservation, Department of Food Technology, Safety and Health, Member of Food2Know, Faculty of Bioscience Engineering, Ghent University, Belgium.
Food Microbiol. 2019 Dec;84:103243. doi: 10.1016/j.fm.2019.103243. Epub 2019 Jun 16.
This study evaluated the effect of both gaseous and dissolved oxygen (O) concentration (0 - 21%) on the growth of six heat-resistant moulds (HRMs) (Neosartorya and Byssochlamys spp.) previously isolated from high-acid fruit products. The study was performed in acidified potato dextrose agar (aPDA) with all six HRMs and with B. fulva and N. fischeri in strawberry, apple and orange juice-based media. At ≥ 0.15% O, visible growth of the HRMs occurred within 3-6 days. Complete inhibition on aPDA did not occur even at very low levels of dissolved O (ca. 0.01% O). With the exception of B. fulva, decrease of the O concentration to ≤0.03% resulted in significantly (p < 0.05) longer times to visible growth. The growth of N. laciniosa, N. fischeri, B. nivea and B. fulva was inhibited for 30 days when they were incubated under strict anaerobic conditions. As in aPDA, B. fulva and N. fischeri grew in the three fruit-based media at O concentrations ≥0.15%. Significantly slower (p < 0.05) growth was observed for N. fischeri in orange juice medium. Strategies to inhibit the growth of HRMs should therefore not be based entirely on establishing low headspace O levels. With this in mind, the effect of low O concentrations (<1%) should be studied in combination with other factors (hurdles) such as antioxidants, organic acids, sugars (a), storage temperature and pasteurization intensity, in order to predict the growth inhibition of the HRMs.
本研究评估了气态氧和溶解氧（O）浓度（0-21%）对先前从高酸水果产品中分离出的六种耐热霉菌（HRMs）（Neosartorya 和 Byssochlamys spp.）生长的影响。该研究在酸化的土豆葡萄糖琼脂（aPDA）中进行，使用了所有六种 HRMs，以及在草莓、苹果和橙汁基培养基中使用了 B. fulva 和 N. fischeri。在 O 浓度≥0.15%时，HRMs 在 3-6 天内可见生长。即使在溶解氧（约 0.01% O）非常低的情况下，也不会完全抑制 aPDA 上的生长。除了 B. fulva 之外，当 O 浓度降至≤0.03%时，可见生长的时间明显（p<0.05）延长。当 N. laciniosa、N. fischeri、B. nivea 和 B. fulva 在严格的厌氧条件下孵育时，它们的生长被抑制了 30 天。与在 aPDA 中一样，B. fulva 和 N. fischeri 在三种基于水果的培养基中在 O 浓度≥0.15%时生长。在橙汁培养基中，N. fischeri 的生长明显（p<0.05）较慢。因此，抑制 HRMs 生长的策略不应完全基于建立低顶空 O 水平。考虑到这一点，应结合其他因素（障碍），如抗氧化剂、有机酸、糖（a）、储存温度和巴氏杀菌强度，研究低 O 浓度（<1%）的影响，以预测 HRMs 的生长抑制。
