Titus T C, Acton J C, McCASKILL Linda, Johnson M G
Food Science Department and Microbiology Department, Clemson University, Clemson, South Carolina 29631.
J Food Prot. 1978 Aug;41(8):606-612. doi: 10.4315/0362-028X-41.8.606.
Exterior surfaces of beef plates were inoculated with aerobic mesophilic, psychrotrophic, coliform, fecal coliform and Staphylococcus aureus bacteria before spraying with city water (7.03 kg/cm) or with 100, 150 or 200 ppm hypochlorite solutions applied at 3.75, 5.25 or 7.03 kg/cm) for 12 sec. Surface strips excised from the inoculated carcass regions were analyzed for bacterial persistence at 2 hand 2,4,8,16 and 20 days after spray treatment. A one log. or greater, reduction incoliforms, fecal coliforms and S. aureus counts occurred within 4 days for each spray treatment. Initial aerobic mesophilic and psychrotrophic counts were reduced by < 1 log within 2 h but increased to original inoculum levels within 8 days for each treatment. Mesophilic and psychrotrophic counts increased to > 3.5 logs higher than inoculated levels after 16 days at 4-6 C. Spray pressure (P < .01) was more effective in reducing mesophilic, psychrotrophic and S. aureus counts than was hypochlorite concentration (P < .05) while both variables were about equally effective against coliforms (P < .01) and fecal coliforms (P < .05). Surprisingly, reductions of psychrotrophic, coliform and S. aureus counts on the beef carcass surface sprayed with hypochlorite solutions were not significantly (P < .05) different from those observed on carcasses sprayed with city water. However, a significantly (P < .05) greater reduction in aerobic mesophile and fecal coliform counts at 2 days after treatment was obtained when using the intermediate spray pressure of 5.25 kg/cm containing 200 ppm hypochlorite, rather than city water. No undesirable change in beef grade, muscle shear or color property was observed for carcasses treated with the hypochlorite solutions.
在对牛肋条的外表面接种嗜温需氧菌、嗜冷菌、大肠菌群、粪大肠菌群和金黄色葡萄球菌后，分别用市政用水（7.03千克/平方厘米）或浓度为100、150或200 ppm的次氯酸盐溶液，以3.75、5.25或7.03千克/平方厘米的压力喷洒12秒。从接种后的胴体区域切取表面条带，在喷雾处理后的第2、4、8、16和20天分析细菌残留情况。每次喷雾处理后4天内，大肠菌群、粪大肠菌群和金黄色葡萄球菌数量减少了一个对数或更多。初始嗜温需氧菌和嗜冷菌数量在2小时内减少不到一个对数，但每种处理在8天内又回升到原始接种水平。在4 - 6摄氏度下放置16天后，嗜温菌和嗜冷菌数量增加到比接种水平高3.5个对数以上。喷雾压力（P < 0.01）在减少嗜温菌、嗜冷菌和金黄色葡萄球菌数量方面比次氯酸盐浓度（P < 0.05）更有效，而这两个变量对大肠菌群（P < 0.01）和粪大肠菌群（P < 0.05）的效果大致相同。令人惊讶的是，用次氯酸盐溶液喷洒的牛胴体表面，嗜冷菌、大肠菌群和金黄色葡萄球菌数量的减少与用市政用水喷洒的胴体相比，差异不显著（P < 0.05）。然而，使用含200 ppm次氯酸盐、压力为5.25千克/平方厘米的中间喷雾压力处理时，处理后2天需氧嗜温菌和粪大肠菌群数量的减少显著（P < 0.05）大于使用市政用水处理的情况。用次氯酸盐溶液处理的胴体在牛肉等级、肌肉剪切力或颜色特性方面未观察到不良变化。
