Abstract：
The use of air jet impingement to remove residues from surfaces in food manufacturing operations offers an alternative to the use of water and liquid cleaning agents. During this investigation, air impingement was used to remove nonfat dry milk (NFDM) residues from a stainless-steel surface. The influence of the water activity (aw ) of the residue, the time after the residue reached an equilibrium water activity, and the thickness of residue at the time of removal from the surface have been investigated. All three factors had a significant effect on the time for removal. An increase in the water activity, the time at equilibrium, the sample thickness, or a combination of all three resulted in an increase in the time required to remove the deposits. Visible changes in the structure of deposits were observed as NFDM samples equilibrated to water activities above 0.43. NFDM residues with water activities less than 0.33 were removed within 1 s of using air impingement regardless of wall shear stress. When the water activities were greater than 0.50, the thickness of deposit was greater than 1 mm, and the time after reaching an equilibrium water activity was over 7 days, more than 5 min of air impingement with wall shear stress over 9.48 Pa was required to remove the residue. The results from these experiments indicated that air impingement has the potential to provide effective cleaning in manufacturing facilities for low-moisture foods. PRACTICAL APPLICATION: The introduction of water in low-moisture food environments is often undesirable due to the possibility of pathogenic microorganism growth. The normal cleaning operations in the food industry use water as a cleaning agent. This study evaluates the application of air impingement technology as a dry-cleaning method.
摘要：
在食品制造操作中使用空气喷射冲击从表面去除残留物提供了使用水和液体清洁剂的替代方案。在这次调查中,空气冲击用于从不锈钢表面去除脱脂奶粉（NFDM）残留物。残渣的水活度（aw）的影响，残留物达到平衡水活度后的时间，并研究了从表面去除时残留物的厚度。所有这三个因素对去除时间都有显著影响。水活度的增加，处于平衡状态的时间，样品厚度,或所有三者的组合导致去除沉积物所需的时间增加。当NFDM样品平衡到高于0.43的水活度时，观察到沉积物结构的可见变化。水活度小于0.33的NFDM残留物在使用空气冲击的1s内被去除，而与壁切应力无关。当水活度大于0.50时,沉积物厚度大于1mm,达到平衡水分活度后的时间超过7天，去除残留物需要超过5分钟的空气冲击，壁切应力超过9.48Pa。这些实验的结果表明，空气冲击有可能为低水分食品的生产设施提供有效的清洁。实际应用:由于病原微生物生长的可能性,在低水分食品环境中引入水通常是不希望的。食品工业中的正常清洁操作使用水作为清洁剂。这项研究评估了空气冲击技术作为干洗方法的应用。
