Zhang Yue, Chen Huaiqiong, Critzer Faith, Davidson P Michael, Zhong Qixin
Department of Food Science and Technology, 2510 River Drive, University of Tennessee, Knoxville, Tennessee 37996, USA.
J Food Prot. 2017 Jun;80(6):994-1001. doi: 10.4315/0362-028X.JFP-16-359.
The objective of this study was to evaluate the potential of cinnamon oil emulsions as alternative washing solutions to improve the microbial safety of carrots. Whey protein concentrate (WPC), gum arabic (GA), lecithin, and their combinations were used to prepare cinnamon oil emulsions. The emulsions were characterized for their hydrodynamic diameter (D) during 7 days of storage and their antimicrobial activity against cocktails of Salmonella enterica , Escherichia coli O157:H7, and Listeria monocytogenes . The D of the emulsion prepared with the GA+WPC blend did not change significantly (195.0 to 184.1 nm), whereas all other emulsions showed varying degrees of increases in D. Compared with free cinnamon oil dissolved in 5% ethanol, all emulsions showed similar or lower MICs and MBCs. Emulsions prepared with GA and equal masses of GA and WPC were chosen and diluted to 0.2 and 0.5% cinnamon oil to wash carrots that were surface inoculated with bacterial cocktails because of their lower MICs and MBCs than free oil. Emulsions resulted in significantly higher reductions of pathogens on carrots than free cinnamon oil, 3.0 to 3.7 versus 2.1 to 2.3 log CFU/g at 0.5% cinnamon oil and 2.0 to 3.0 versus 1.0 to 1.7 log CFU/g at 0.2% cinnamon oil. No transfer of bacteria from inoculated carrots to wash solutions and no effects of organic load on log reductions were only observed for wash treatments with 0.5% emulsified cinnamon oil. Thus, the cinnamon oil emulsions are potential alternative postharvest washing solutions for fresh produce production.
本研究的目的是评估肉桂油乳剂作为替代洗涤溶液以提高胡萝卜微生物安全性的潜力。使用乳清蛋白浓缩物（WPC）、阿拉伯胶（GA）、卵磷脂及其组合来制备肉桂油乳剂。对乳剂在储存7天期间的流体动力学直径（D）及其对肠炎沙门氏菌、大肠杆菌O157:H7和单核细胞增生李斯特氏菌混合菌的抗菌活性进行了表征。用GA+WPC混合物制备的乳剂的D没有显著变化（195.0至184.1纳米），而所有其他乳剂的D均呈现不同程度的增加。与溶解在5%乙醇中的游离肉桂油相比，所有乳剂均表现出相似或更低的最低抑菌浓度（MIC）和最低杀菌浓度（MBC）。由于GA以及等量GA和WPC制备的乳剂的MIC和MBC低于游离油，因此选择这些乳剂并将其稀释至0.2%和0.5%的肉桂油浓度来清洗表面接种了细菌混合菌的胡萝卜。乳剂对胡萝卜上病原体的减少效果显著高于游离肉桂油，在0.5%肉桂油浓度下，分别为3.0至3.7 log CFU/g和2.1至2.3 log CFU/g，在0.2%肉桂油浓度下，分别为2.0至3.0 log CFU/g和1.0至1.7 log CFU/g。仅在使用0.5%乳化肉桂油的洗涤处理中观察到没有细菌从接种的胡萝卜转移到洗涤溶液中，并且有机负荷对对数减少没有影响。因此，肉桂油乳剂是新鲜农产品生产中潜在的替代采后洗涤溶液。
