Halpin-Dohnalek Margaret I, Marth Elmer H
Department of Food Science and The Food Research Institute, University of Wisconsin-Madison, Madison, Wisconsin 53706.
J Food Prot. 1989 Dec;52(12):863-866. doi: 10.4315/0362-028X-52.12.863.
This study determined growth and survival of Staphylococcus aureus strains 100-A, 196-E, 254, 473, 505, and 521 in whipped butter made by whipping butter produced from inoculated cream or in whipped butter inoculated after manufacture. Cream was inoculated to contain ca. 10 to 10 S. aureus /ml and then was held at 4°C for 3 d, at 22°C for 36 h, or at 37°C for 24 h. After incubation, cream was churned to obtain butter which then was either lightly salted (1.0%, w/w) or left unsalted. Fresh sweet cream also was churned to obtain sweet cream butter which was lightly salted or left unsalted. Sweet cream butter was inoculated to contain ca. 10 S. aureus /g. Butter containing S. aureus was brought to 15°C and whipped for 5-7 min with a three-speed hand mixer. Whipped butter was held at 4, 10, 15, and 25°C for up to 6 weeks. Whipping of butter influenced growth and survival of all strains of S. aureus . Whipped butter inoculated after churning and before whipping was a better medium for growth of the pathogen than was whipped butter made from butter that had been churned from inoculated cream. Whipping of butter had a greater effect than salt on the ability of S. aureus to grow or survive. Variability among strains also was important in determining growth and survival of S. aureus in whipped butter.
本研究测定了金黄色葡萄球菌菌株100 - A、196 - E、254、473、505和521在由接种奶油制成的搅打奶油中或在制造后接种的搅打奶油中的生长和存活情况。将奶油接种至含有约10至10⁵/ml的金黄色葡萄球菌，然后在4°C下保存3天，在22°C下保存36小时，或在37°C下保存24小时。培养后，将奶油搅拌制成黄油，然后要么轻度加盐（1.0%，w/w），要么不加盐。新鲜甜奶油也进行搅拌以获得轻度加盐或不加盐的甜奶油黄油。将甜奶油黄油接种至含有约10⁵/g的金黄色葡萄球菌。将含有金黄色葡萄球菌的黄油加热至15°C，并用三速手动搅拌器搅拌5 - 7分钟。搅打奶油在4、10、15和25°C下保存长达6周。黄油的搅打影响了所有金黄色葡萄球菌菌株的生长和存活。搅打后但在搅打前接种的搅打奶油比由接种奶油搅拌制成的黄油制成的搅打奶油更有利于病原体的生长。黄油的搅打对金黄色葡萄球菌生长或存活能力的影响比盐更大。菌株间的变异性在确定金黄色葡萄球菌在搅打奶油中的生长和存活情况时也很重要。
