The contamination of raw materials, packaging, or processing environments by fungal ascospores is a real concern for food industries, where variable rates of spoilage can be reached in pasteurized acidic products such as fruit juices, fruit jams, or soft drinks. The aim of this work was to assess the combined effect of aw and pH on the growth of six isolates from three genera of ascospore-forming molds that may occur in raw materials and in food industrial environments, in order to determine the environmental conditions that prevent the spoilage of pasteurized foods and beverages. Growth tests were carried out on 60-day-old ascospores from Aspergillus hiratsukae (≡Neosartorya hiratsukae), Aspergillus thermomutatus (≡Neosartorya pseudofischeri), Chaetomium flavoviride, Chaetomium globosum, Talaromyces bacillisporus, and Talaromyces trachyspermus. The tests were performed up to 90 days at 25 °C, using sucrose solutions at different aw (0.85, 0.88, 0.92, 0.95) and pH (3.20, 3.50, 3.80, 4.20, 4.60) values. Growth was characterized by fitting an ordinary logistic regression model to the collected growth data. The explained percentage of the growth/no growth models ranged between 81.0 and 99.3%: aw exerted the largest influence on the growth of all tested species, while pH was significant only for Chaetomium isolates. The minimum conditions for germination and growth were aw 0.92 and pH 3.50 or 3.80, respectively, for C. flavoviride (46 days) and C. globosum (39 days), aw 0.92 and pH 3.20 for T. trachyspermus (13 days), aw 0.88 and pH 3.20 for T. bacillisporus (39 days), and aw 0.88 and pH 3.20 for the two aspergilli (33 and 27 days, respectively, for A. hiratsukae and A. thermomutatus). Most of the spoiling mycetes tested were well-adapted to the formulations considered; therefore, foods strategies aiming to inhibit their growth should explore also the hurdle effect exerted by other factors (e.g., antioxidants, organic acids, oxygen levels).

中文翻译：

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水分活度和pH值对与食物相关的形成孢子的霉菌生长的综合影响

真菌子囊孢子对原材料，包装或加工环境的污染是食品工业的真正关注点，在巴氏消毒的酸性产品（例如果汁，果酱或软饮料）中可以达到可变的腐败率。这项工作的目的是评估aw和pH值对原料和食品工业环境中可能发生的三种孢子形成霉菌的六种分离菌的生长的综合影响，从而确定可防止感染的环境条件。巴氏杀菌食品和饮料的变质。在来自hiratsukae（≡Neosartoryahiratsukae），thermomutatus（≡Neosartoryapseudofischeri），Chaetomium flavoviride，Chaetomium globosum，Talaromyces bacillisporus和Talaromyces trachy的60日龄子囊孢子上进行生长测试。使用不同aw（0.85，0.88，0.92，0.95）和pH（3.20，3.50，3.80，4.20，4.60）值的蔗糖溶液在25°C下进行长达90天的测试。通过将普通的逻辑回归模型拟合到收集的增长数据来表征增长。解释的生长/不生长模型百分比在81.0至99.3％之间：aw对所有受测物种的生长影响最大，而pH仅对拟杆菌属分离物有意义。黄曲霉梭菌（46天）和球孢梭菌（39天）的最低发芽和生长条件分别为aw 0.92和pH 3.50或3.80，a。trachyspermus（13天），aw为0.92和pH 3.20 T. bacillisporus（39天）为0.88和pH 3.20，两个曲霉菌（A. hiratsukae和A. thermomutatus）分别为0.88和pH 3.20（分别为33和27天）。测试的大多数变质真菌都非常适合所考虑的配方。因此，旨在抑制其生长的食品策略也应探讨其他因素（例如抗氧化剂，有机酸，氧气水平）产生的障碍效应。