膨化生产SPF动物饲料的尝试

On the Experiment for Production of SPF Animal Feed by Extrusion

试验使用DSE-25型双螺杆挤压膨化机,采用4因素3水平正交试验设计L9(34),就膨化前的水分含量、喂料速度、螺杆转速和膨化温度对饲料灭菌效果的影响进行了研究。结果表明:①大肠杆菌、霉菌和酵母对膨化比较敏感,经过80℃的膨化后,都未检出。②四个因素对饲料中菌落总数都有极显著影响(P<0.01),其影响程度为:膨化温度最大,膨化前的水分含量、喂料速度、螺杆转速的影响力一样。③最优工艺参数为:膨化前的水分含量23%、喂料速度24 r/min、螺杆转速150 r/min和膨化温度120℃。④只要能够避免冷却、输送、打包等后续工序中的二次污染,就能够生产出符合SPF动物的饲料。

The twin-screw extruder Type DSE - 25 was used for experiment, and the impact of the moisture content, feeding rate, screw speed and extruding temperature on sterilization effect of the feed before extruding was studied by adopting L9 （ 3^4 ） （ 4 factors and 3 levels orthogonal experimental design ）. The results were shown as follows ： （ 1 ） The coliform, mildew and yeast were highly sensitive to extruding, so that they could be killed by extruding at 80℃; （ 2 ） All of four determined factors had the obvious effect （ P 〈 0.01 ） on total colony quantity in the feeds, its effect degree： extruding temperature 〉 moisture content before extruding = feeding rate = screw speed; （3） The optimum process： 23% moisture content before extruding, 24 r/min feeding rate, 150 r/min screw speed and 120℃ extruding temperature; （4） The qualified feeds could be produced for SPF animal if only the secondary pollution could be avoided in subsequent handling, such as cooling, conveying, packing and so on.