UVC-GA抑制牡蛎肉质表面E.coli O157:H7生长

UV-C-irradiated Gallic Acid Solution (UVC-GA) Inhibited the Growth of E. coli O157:H7 on the Surface of Oyster Flesh

摘要:

紫外辐射食没子酸抑菌液（UVC-GA）是通过紫外线短波（UV-C）辐照没食子酸（GA）开发一种新型光诱导增强GA抑菌的方法，将UV-C辐照GA 12 h形成新型UVC-GA抑菌液，E. coli O157：H7减少量达3.57 log cfu/mL，比GA显著高22.33倍。UVC-GA的抑菌活性受辐照时间、波长和pH的影响，60 min辐照后使E. coli O157：H7减少4.42 log cfu/mL，比紫外线中波UVB-GA和紫外线长波UVA-GA显著高64.25%和223.47%，pH 3下比pH 7和pH 11分别高94.23倍和87.62倍。UVC-GA加入苯磺酸（BSA）后抗菌活性显著降低至0.63 log cfu/mL（p<0.05），说明UVC-GA内的醌类化合物增强了其抗菌活性。加入活性氧（ROS）猝灭剂，UVC-GA比二甲基亚甲砜（DMSO）和甘露醇处理组比UVC-GA抗菌效果显著降低了4.56%和8.15%（p<0.05），且UVC-GA内有过氧化氢的生成及E. coli O157：H7氧化应激水平增加，表明ROS在UVC-GA的抗菌作用中也起着一定的作用。结果表明，UVC-GA可有效抑制牡蛎肉质表面E. coli O157：H7，正确处理UV-C辐照的GA可作为一种新型抑菌液应用于牡蛎或其它食品的抑菌。

Abstract:

A novel ultraviolet-irradiated gallic acid antibacterial solution (UVC-GA) was developed using a new method of light-induced enhancement of GA antibacterial activity through exposing gallic acid (GA) to UV-C for 12 h. The GA solution obtained after UVC-GA for 12 h could reduce E. coli O157: H7 by 3.57 log cfu/mL (which was 22.33 times higher than that of GA. The antibacterial activity of UVC-GA solution was affected by the irradiation duration, wavelength and pH. After 60 min of irradiation, UVC-GA reduced E. coli O157: H7 by 4.42 log cfu/mL, which was significantly higher than UVB-GA and UVA-GA by 64.25% and 223.47%; The reduction of E. coli O157: H7 by UVC-GA at pH 3 was 94.23 and 87.62 times, respectively, higher than those at pH 7 and pH 11. The addition of benzenesulfinic acid (BSA) to UVC-GA lowered E. coli O157: H7 to 0.63 log cfu/mL (p<0.05), indicating that quinone compounds in UVC-GA enhanced its antibacterial activity. The addition of reactive oxygen species (ROS) quencher to UVC-GA significantly (p<0.05) reduced the antibacterial effect by 4.56% and 8.15%, respectively, compared with those of the DMSO-treated group and the mannitol-treated group (p<0.05). The generation of hydrogen peroxide and the increase of E. coli O157: H7-induced oxidative stress indicated the contribution of ROS to the antibacterial effect of UVC-GA. The results showed that UVC-GA could effectively inhibit E. coli O157:H7 on the surface of oyster flesh, and correctly treated UV-C irradiated GA can be used as a novel antimicrobial solution for sterilization of oyster products and other foods.