Food Safety Intervention Technologies Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA.
J Food Prot. 2010 May;73(5):812-8. doi: 10.4315/0362-028x-73.5.812.
Antimicrobial films of polylactic acid polymer incorporated with nisin, EDTA, sodium benzoate (SB), potassium sorbate (PS), and their combinations were developed, and their antimicrobial effects on the inactivation of Escherichia coli O157:H7 and natural background microflora (total aerobic bacteria, molds, and yeasts) in strawberry puree at 10 and 22 degrees C were determined. Direct addition of SB+PS to strawberry puree was also used as a comparison with SB+PS film treatment. The combination treatment reduced the cell populations of E. coli O157:H7 from 3.5 log CFU/ml to undetectable levels (<1 CFU/ml) after 14 days and 1 day at 10 and 22 degrees C, respectively, while the cells of E. coli O157:H7 in control samples survived up to 48 days at 10 degrees C and more than 14 days at 22 degrees C. The SB+PS film treatment produced a greater reduction of population of E. coli O157:H7 cells than did the SB+PS direct addition treatment. Similar results were observed for inactivation of natural microflora. In general, the antimicrobial effect was in the following order: film combination > SB+PS film > SB+PS direct addition > EDTA film > nisin film. The data obtained in this study suggest two approaches toward the development of control interventions against E. coli O157:H7 and extension of the microbiological shelf life of strawberry puree: (i) using antimicrobial packaging and (ii) using combinations of preservatives. The film formulas developed here can be used to make bottles or as coatings on the surface of bottles for use in liquid food packaging.
聚乳酸聚合物中加入乳链菌肽、EDTA、苯甲酸钠（SB）、山梨酸钾（PS）及其组合的抗菌膜被开发出来，并在 10 和 22°C 下研究了其对草莓泥中大肠杆菌 O157:H7 和天然背景微生物（总需氧细菌、霉菌和酵母）的失活的抗菌效果。直接添加 SB+PS 到草莓泥中也与 SB+PS 膜处理进行了比较。组合处理在 10 和 22°C 下分别在 14 天和 1 天内将大肠杆菌 O157:H7 的细胞数从 3.5 log CFU/ml 减少到不可检测水平（<1 CFU/ml），而对照样品中的大肠杆菌 O157:H7 细胞在 10°C 下可存活至 48 天，在 22°C 下可存活超过 14 天。SB+PS 膜处理比 SB+PS 直接添加处理产生更大的大肠杆菌 O157:H7 细胞数量减少。对天然微生物群的失活也观察到了类似的结果。一般来说，抗菌效果的顺序为：膜组合>SB+PS 膜>SB+PS 直接添加>EDTA 膜>乳链菌肽膜。本研究获得的数据表明了两种针对大肠杆菌 O157:H7 控制干预措施的发展和草莓泥微生物保质期延长的方法：（i）使用抗菌包装和（ii）使用防腐剂组合。这里开发的膜配方可用于制作瓶子或作为瓶子表面的涂层，用于液体食品包装。
