PHYSICAL AND MICROBIOLOGICAL QUALITY OF OPAQUE, SANITIZED, AND CHILLED QUAIL EGGS EXPERIMENTALLY CONTAMINATED WITH Salmonella enteric SER. TYPHIMURIUM

Abstract The objective of this study was to verify the physical, chemical and microbiological quality of Japanese quail eggs artificially contaminated withSalmonella enterica ser. Typhimurium. The eggs were sanitized and stored at different temperatures (between 5 and 25 ºC) for 27 days. We used 768 eggs with opaque shells, typical pigments of the species, and average weight of 11 g. The experimental design was completely randomized in a 2x2x2 factorial arrangement (contamination x sanitation x cooling) with six replications and one egg per experimental unit. The eggs were contaminated by handling with 1.5 x 105 colony forming unit (CFU) ofSalmonella. Typhimurium / mL and sanitized according to the treatments with a 5 ppm Cl solution. The data were subjected to analysis of variance and t test. Bacterial contamination has damaged the egg weight, Haugh unit, yolk index and albumen, and pH of yolk and albumen, from 18 days of storage. The egg storage time and storage temperature affected the internal quality of quail eggs in all variables. The worst internal quality was observed in eggs stored at 25 ºC. The sanitation and cooling reduced the growth of Salmonella in contaminated eggs. Eggs in opaque shell, when not refrigerated, should be consumed within 18 days after laying.

摘要 本研究旨在验证人工污染肠炎沙门氏菌鼠伤寒血清型（Salmonella enterica ser. Typhimurium）的日本鹌鹑蛋的物理、化学及微生物学品质。实验选用768枚带有该物种典型色素的不透明蛋壳鹌鹑蛋，平均重量为11 g，经消毒处理后置于5~25 ℃的不同温度下储存27天。本实验采用完全随机的2×2×2因子设计（污染×消毒×冷藏），设置6次重复，每个实验单元使用1枚蛋。实验通过以1.5×10^5菌落形成单位（CFU）/mL的鼠伤寒沙门氏菌菌液处理完成蛋的人工污染，并依据实验方案采用5 ppm氯溶液对蛋体进行消毒。对所得实验数据进行方差分析与t检验。结果显示，自储存第18天起，沙门氏菌污染会对蛋重、哈氏单位（Haugh unit）、蛋黄指数及蛋清品质，以及蛋黄与蛋清的pH值造成显著损害。鹌鹑蛋的储存时长与储存温度对所有内部品质指标均存在显著影响，其中在25 ℃下储存的鹌鹑蛋内部品质最差。消毒与冷藏措施可有效抑制污染蛋体内沙门氏菌的增殖。针对带有不透明蛋壳的鹌鹑蛋，若未进行冷藏，应在产蛋后18天内食用完毕。