Kang Young-Jae, Frank Joseph F
Department of Food Science and Technology, University of Georgia, Athens, GA 30602.
J Food Prot. 1989 Jul;52(7):512-524. doi: 10.4315/0362-028X-52.7.512.
Processing plant air is a source of post-pasteurization contamination of dairy products. Little is known about the extent to which biological aerosols contaminate pasteurized products, however evidence indicates that air within a packaging area is a critical control point for both pathogens and spoilage microorganisms. Consequently, it is important to understand the characteristics of biological aerosols, learn how to control their occurrence, and discover practical and valid monitoring methods. Methods used for monitoring viable particles in air include the use of sedimentation plates, impingers, slit and sieve impactors, filters, and centrifugal samplers. Each of these methods has limitations on its usefulness for dairy plant air monitoring. Microorganisms are often injured due to the stresses of the aerosolized state and consequently may not grow on selective media. Sampling methods such as impingement and filtration which subject the organisms to additional stress may cause sufficient injury to prevent growth on non-selective media. However, gentler collection methods such as centrifugal samplers may not generate enough force to collect the smallest viable particles. Aerosols are generated within the dairy plant by worker activity, sink and floor drains, water spraying, and air conditioning systems. Environmental sanitation, air filtration, air flow control, and control over personnel cleanliness and activity are useful control measures. The adoption of "clean room" design principles for a packaging area will aid in controlling biological aerosols in new dairy processing plants.
加工厂空气是乳制品巴氏杀菌后污染的一个来源。关于生物气溶胶对巴氏杀菌产品的污染程度，人们了解甚少，不过有证据表明，包装区域内的空气对于病原体和腐败微生物而言都是关键控制点。因此，了解生物气溶胶的特性、掌握如何控制其产生以及找到切实有效的监测方法很重要。用于监测空气中活颗粒的方法包括使用沉降平板、冲击式采样器、狭缝和筛孔冲击器、过滤器以及离心采样器。这些方法中的每一种在用于乳制品厂空气监测时都有其局限性。微生物常常会因雾化状态带来的压力而受损，因此可能无法在选择性培养基上生长。诸如冲击和过滤之类的采样方法会使微生物承受额外压力，可能造成足够的损伤，从而使其无法在非选择性培养基上生长。然而，诸如离心采样器之类较为温和的采集方法可能无法产生足够的力量来采集最小的活颗粒。乳制品厂内的气溶胶是由工人活动、水槽和地漏、喷水以及空调系统产生的。环境卫生、空气过滤、气流控制以及对人员清洁度和活动的控制都是有用的控制措施。在包装区域采用“洁净室”设计原则将有助于在新建乳制品加工厂中控制生物气溶胶。
