Maxcy R B
Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska 68583.
J Food Prot. 1978 Jun;41(6):435-438. doi: 10.4315/0362-028X-41.6.435.
Culture, distribution, and preparation of lettuce for salad offers opportunities for contamination with and growth of microorganisms. Protection and preservation methods, even when appropriate, may likewise be favorable for the contaminants. Fresh lettuce, as commercially available, was studied to determine the magnitude of contamination and the nature of representative contaminants. Specific contaminants of public health interest were added to test portions to determine their fate during storage of lettuce as a salad at room temperature. Storage of lettuce in bowls on ice resulted in very little cooling of most of the lettuce. Microbial plate counts on fresh lettuce commonly were over 10/g and the diversity of the microflora indicated a generally favorable microenvironment for many types of bacteria. Inocula of Salmonella typhimurium , Escherichia coli , and Staphylococcus aureus fared well on lettuce salad and were able to grow at room temperature storage. Commmercial "whitener" added to lettuce to preserve freshness reduced the total microflora and indicator organisms of public health significance.
用于制作沙拉的生菜的培养、分布和准备为微生物的污染和生长提供了机会。即使采用适当的保护和保存方法，同样可能有利于污染物。对市售的新鲜生菜进行了研究，以确定污染程度和代表性污染物的性质。将具有公共卫生意义的特定污染物添加到测试样本中，以确定它们在室温下作为沙拉储存的生菜中的变化情况。将生菜放在碗里加冰储存，大多数生菜几乎没有降温。新鲜生菜上的微生物平板计数通常超过每克10个，微生物群落的多样性表明对许多类型的细菌来说，这里通常具有良好的微环境。鼠伤寒沙门氏菌、大肠杆菌和金黄色葡萄球菌接种到生菜沙拉上后生长良好，并且在室温储存条件下能够繁殖。添加到生菜中以保持新鲜度的商业“增白剂”减少了具有公共卫生意义的总微生物群落和指示生物。
