假单胞菌噬菌体PrH181对大黄鱼块防腐效果的研究

为控制大黄鱼块中假单胞菌引起的腐败作用，本研究测试了1株假单胞菌裂解性噬菌体PrH-181在4℃有氧冷藏条件下对大黄鱼的防腐作用效果。经102~108 pfu/mL范围内不同效价噬菌体处理无菌大黄鱼汁后30℃培养至14 h，OD_{620 nm}测定结果显示，噬菌体效价大于103 pfu/mL时就具有显著（P<0.05）的抑菌活性。从鱼块菌落数、pH和TVB-N含量等腐败临界关键指标变化来看，对照组中的假单胞菌落数在第4 d时就达到了临界值106 cfu/g，pH在第2 d时就降到了最低点，TVB-N含量在第4 d时已经超过临界值30 mg/100 g；而对104和106 pfu/mL的噬菌体处理组来说，假单胞菌落数分别于第10和12 d才达到临界值106 cfu/g，最低pH出现时间分别为第8和12 d，TVB-N含量分别于第12和14 d才超过临界值。可见噬菌体PrH-181对大黄鱼块的保鲜效果明显，且效价越高保鲜效果越好。

Antiseptic Effect of Pseudomonas Bacteriophages PrH-181 on Large Yellow Croaker Meat

In order to control the spoilage of raw large yellow croaker fillets caused by Pseudomonas.The antibacterial ability of the Pseudomonas bacteriophage PrH-181 against the spoilage of large yellow croaker under aerobic refrigeration at 4℃was studied.After treating the fish juice with different titer of 10² to 10⁸ pfu/mL,incubating for 14 h at 30℃,the results of OD_620nm showed the bacteriophage PrH-181 exhibited significant(P<0.05)antibacterial activity,when its titer was greater than 10³ pfu/mL.From the change of colony numbers,pH and TVB-N concentration which characterize the extent of spoilage,as for the control,there were 10⁶ cfu/g Pseudomonas,which was the critical value as symbolic of spoilage beginning,in the fourth day,and the minimun pH occurred in the second day,and the TVB-N concentration exceeded the critical value 30 mg/100 g on the fourth day.As for 10⁴ pfu/mL and 10⁶ pfu/mL phage-treated group,the time for the critical value of colony numbers occurred on the 10th and 12th day,and minimum pH occurred on the 8th and 12th day,TVB-N concentration was up to the critical value on the 12th and 14th day.So,it could be inferred that the preservation effect of bacteriophage PrH-181 on the large yellow croaker was obvious,and the higher the titer was,the better the preservation effect would be.