Fischer J R, Fletcher D L, Cox N A, Bailey J S
Department of Poultry Science, University of Georgia, Athens, Georgia, 30602 and USDA - ARS, Richard B. Russell Agricultural Research Center, Athens, Georgia 30613.
J Food Prot. 1985 Mar;48(3):252-256. doi: 10.4315/0362-028X-48.3.252.
Hard-cooked and peeled eggs were placed in .5, .75 or 1.0% citric acid solutions (with .2% sodium benzoate) and held at 4°C for 30 d (experiment 1), or in .75% acid and held at 4°C for 21 d (experiment 2) to allow equilibration. Following equilibration, the solutions were sampled for pH and total plate counts and then inoculated with either 10 or 10,000 cells each of Salmonella typhimurium , Yersinia enterocolitica , Escherichia coli and Staphylococcus aureus . The eggs were stored for an additional 10 d at 4°C (experiment 1) or for 10 and 24 d at either 1.2, 7.2 or 12.8°C (experiment 2) before sampling for pH, aerobic plate count, total Enterobacteriaceae and each of the individual inoculated test organisms. No growth was detected in the solutions following the 30- and 21-d equilibration periods. The .75% citric acid solution was adequate in reducing the bacterial population and retarding growth of the inoculated organisms. Storage temperature appeared to have little influence on growth of inoculated organisms. Results indicate that the microbiological quality of hard-cooked eggs stored in citric acid based solutions was more dependent on acid concentration than on temperature in resisting bacterial growth following potential recontamination.
将煮熟并去皮的鸡蛋置于0.5%、0.75%或1.0%的柠檬酸溶液（含0.2%苯甲酸钠）中，在4℃下放置30天（实验1），或置于0.75%的酸溶液中，在4℃下放置21天（实验2）以达到平衡。平衡后，对溶液进行pH值和总平板计数采样，然后分别接种10个或10000个鼠伤寒沙门氏菌、小肠结肠炎耶尔森氏菌、大肠杆菌和金黄色葡萄球菌细胞。鸡蛋在4℃下再储存10天（实验1），或在1.2℃、7.2℃或12.8℃下分别储存10天和24天（实验2），然后对pH值、需氧平板计数、总肠杆菌科以及每种接种的测试微生物进行采样。在30天和21天的平衡期后，溶液中未检测到生长。0.75%的柠檬酸溶液足以减少细菌数量并抑制接种微生物的生长。储存温度对接种微生物的生长似乎影响很小。结果表明，在基于柠檬酸的溶液中储存的熟鸡蛋的微生物质量在抵抗潜在再污染后的细菌生长方面，更多地取决于酸浓度而非温度。
