University of Copenhagen, Department of Food Science, Section of Microbiology and Fermentation, Rolighedsvej 26, 1958, Frederiksberg C, Denmark.
University of Copenhagen, Department of Food Science, Section of Microbiology and Fermentation, Rolighedsvej 26, 1958, Frederiksberg C, Denmark.
Food Microbiol. 2020 Dec;92:103574. doi: 10.1016/j.fm.2020.103574. Epub 2020 Jun 25.
Raw egg-based dishes present a safety risk when eggs of uncertain Salmonella status are used. Here, the inactivation of four Salmonella serovars at different combinations of acid, pH and temperature were investigated. Strains of egg or broiler-associated Salmonella serovars Enteritidis, Infantis, Typhimurium, and a heat resistant Senftenberg 775W were tested in broth and egg yolk. It was observed that although S. Senftenberg 775W survived better than its mutant lacking the loci of heat resistance, the wild type per se was not acid tolerant. For all strains, egg yolk acidification with vinegar to pH 3.9 and storage at 25 °C or 8 °C resulted in >4Log(cfu/mL) reductions within 2h or 24h, respectively. At pH 4.2, 2-3Log(cfu/mL) reductions were seen within 6h at 25 °C. In contrast, acidification with lemon juice to pH of 3.9 allowed for growth at 25 °C, while a pH of 2.9 ensured >4Log(cfu/mL) reductions within 24h. Egg yolk and acid form the basis for many recipes and with a ratio of 0.82 of vinegar (≥5% acetic acid) to egg yolk or 1.23 of lemon juice to yolk and storage at 25 °C for 2h or 24h, respectively, a high degree of safety can be obtained, if properly chilled raw eggs are used.
当使用来源不明的鸡蛋时，生蛋制成的菜肴可能存在安全风险。本研究旨在探讨不同酸、pH 值和温度组合对 4 种沙门氏菌血清型的灭活效果。将来源于鸡蛋或肉鸡的肠炎沙门氏菌、婴儿沙门氏菌、鼠伤寒沙门氏菌和耐热型森夫顿 775W 菌株分别在肉汤和蛋黄中进行测试。结果表明，尽管森夫顿 775W 比缺乏耐热基因座的突变体更能耐受酸，但野生型本身并不耐酸。对于所有菌株，将蛋黄用醋酸化至 pH3.9 并在 25°C 或 8°C 下储存，分别在 2h 或 24h 内导致>4Log(cfu/mL)的减少。在 pH4.2 下，25°C 下 6h 内可减少 2-3Log(cfu/mL)。相比之下，用柠檬汁酸化至 pH3.9 可在 25°C 下生长，而 pH2.9 可确保在 24h 内减少>4Log(cfu/mL)。蛋黄和酸是许多食谱的基础，如果使用得当，冷藏的生鸡蛋可以获得很高的安全性，即在蛋黄中加入 0.82 份（≥5%乙酸）的醋或 1.23 份的柠檬汁，然后在 25°C 下储存 2h 或 24h。
