蒙特全球制药行业总监：湿度控制：抑制微生物生长的一种工具

Humidity Control: A tool for reducing microbial growth湿度控制：抑制微生物生长的一种工具

Martin Ginty, 蒙特全球制药行业总监

Martin Ginty,   Pharmaceutical industry director of Munters

郑丽丽，蒙特中国制药行业应用工程师

Lili Zheng， Pharmaceutical industry application engineer of Munters

摘要/ Abstract：

有害微生物的生长一直困扰着许多行业领域，尤其是食品和药品制造商。它们无处不在且难以消除，不断地威胁着人类的健康。霉菌的生长与环境的温度和湿度有着密切的关系，只要将环境的温湿度控制在合理的范围内便可有效抑制霉菌的生长。若湿度控制能将相对湿度控制在50%以下，那么所有微生物的生长都会受到抑制。蒙特在湿度控制领域拥有60多年的丰富经验，已经推出了一系列的解决方案，在任何规模的生产或存储设施中，均可通过降低相对湿度抑制微生物的生长。

Unwanted microbial growth is an ever-present problem in many areas of industry, particularly for food and pharmaceutical manufacturers. They are ubiquitous and difficult to eliminate, constantly threatening human health.  Moulds growth and environmental temperature and humidity have a close relationship, as long as the environmental temperature and humidity control in a reasonable range can effectively inhibit moluds growth.  Humidity control that reduces the relative humidity below 50% will stop all microbial growth. With over 60 years of experience in the field of humidity control, Munters has a range of solutions to control microbial growth by reducing the relative humidity level in any size of production or storage facility.

关键字/Key Words：

微生物无处不在    健康效果   水分  相对湿度   蒙特    湿度控制专家

Microbes everywhere   Health effects   water vapour   relative humidity   Munters   Humidity control specialist

Unwanted microbial growth is an ever-present problem in many areas of industry, particularly for food and pharmaceutical manufacturers. While stringent hygiene procedures, climate control and staff awareness all help to hold microbial growth in check, humidity control is another valuable weapon to add to the arsenal of potential counter-measures.有害微生物的生长一直困扰着许多行业领域，尤其是食品和药品制造商。虽然严格的卫生程序、气候控制和员工意识都有助于控制微生物生长，但湿度控制却是另一种宝贵的潜在对策。

Microbes everywhere.微生物无处不在。

It is an inevitable fact that no matter how hard you try to keep a manufacturing space clean, the world of microbes is continually working against your efforts. While not every microscopic invader is potentially harmful, it does make sense to make the production and storage environment as unwelcoming as possible so they cannot gain a foothold.不论采取多少措施保持生产空间的洁净，微生物也会继续顽强抵抗，这是不可避免的事实。虽然并不是所有的微生物都是有害的，但是它们却会污染生产和存储环境，从而获得立足之地。

To get a feeling for the extent of the challenge, did you know that there are between 10,000 to 1,000,000 fungi spores per cubic meter in the air you are breathing right now? These spores can survive without moisture, remaining dormant for years are even decades. When moisture and a food source become available, the spores germinate and rapidly multiply. They do not even need liquid water to grow, even the moisture present in solid materials or humid air can be sufficient. Uncontrolled mould growth can quickly lead to product quality being compromised, and production areas needing extensive cleaning procedures. For example, the Food and Agriculture Organization (FAO) of the United Nations estimates that 25% of the world's food crops are affected by mycotoxins (poisonous by-products from moulds), resulting in the loss of one billion metric tons of food every year. So any countermeasures that can reduce the growth of mould and other microorganisms will improve profitability and reduce time spent on corrective actions.为了让您切身感受它们存在的范围之广，您知道吗？您现在呼吸的空气中每立方米有10,000至1,000,000个真菌孢子。这些孢子可以在没有水分的情况下保持休眠状态，休眠期甚至可以长达数十年。如果可以获得水分和食物来源，孢子便会萌芽并迅速繁殖。它们不需要液态水也能繁殖，只需固体或潮湿的空气中所含的水分即可。

不受控制的霉菌滋生会迅速造成产品质量下降，生产区域需要采取全面的清洁措施。例如，据联合国粮食与农业组织（FAO）预计，全球有25%的粮食作物感染了霉菌毒素（霉菌分泌的有毒副产物），每年造成的粮食损失达10亿公吨。所以，任何能够控制霉菌和其它微生物滋生的对策都会提高企业的利润，减少应对措施所耗费的时间。

Health effects健康效果

People who are sensitive to mould, or who already suffer from allergies, asthma, or have compromised immune systems and occupy damp or mouldy buildings are at an increased risk of health problems such as inflammatory and toxic responses to mould spores, their by-products and other volatile organic components.对霉菌敏感的人，患有过敏症、哮喘的人，或免疫系统受损并且居住在潮湿发霉的建筑中的人，更容易出现健康问题，比如因霉菌孢子、其副产物和其它挥发性有机成分造成的炎症和毒性反应。

A person's reaction to mould depends on:人类对于霉菌的反应取决于：

Their sensitivity and other health conditions敏感性和其它健康状况

Amount of mould present in the area空间中存在的霉菌量

Type of mould or mould by-products霉菌或霉菌副产物的类型

Length of exposure接触时间

The most common health problem is an allergic reaction while severe reactions are rare but possible. Some moulds, such as Stachybotrys chartarum, also produce mycotoxins that can pose serious health risks. Exposure to high levels of mycotoxins can lead to neurological problems and in some cases death.最常见的健康问题是过敏反应，严重的过敏反应虽很少见，但仍有可能发生。有些霉菌，比如葡萄穗霉，会产生严重威胁健康的霉菌毒素。接触高浓度的霉菌毒素会导致神经受损，有时甚至会导致死亡。

How can humidity control defeat microorganisms? 湿度控制如何能消除微生物呢？

Moisture is needed for any growth to occur but moulds do not need droplets of water to form - water vapour concentrations of greater than 80% relative humidity are sufficient. 任何生物的生长都离不开水分，但是霉菌不需要水分也能生长——水蒸气浓度达到相对湿度80%以上即可。

Fig 1. Effect of relative humidity on mould growth图1.相对湿度对霉菌生长的影响

Source: http://www.ibp.fraunhofer.de/content/dam/ibp/de/documents/Publikationen/Fachzeitschriften/mold_growth_predictiontcm45-35017.pdf资料来源：http://www.ibp.fraunhofer.de/content/dam/ibp/de/documents/Publikationen/Fachzeitschriften/mold_growth_predictiontcm45-35017.pdf

Once the relative humidity level drops below 65%, the probability of mould growth approaches zero. If the relative humidity level of indoor spaces is not controlled, there can be fluctuations during the course of the day and seasonal variations that will increase the risk of mould flourishing. 一旦相对湿度低于65%，几乎不可能滋生霉菌。如果室内的相对湿度未得到控制，在一天中的不同时间段或者随着季节变化，相对湿度会相应改变，霉菌繁殖的风险也会增加。

Once established, some moulds can transport free water to dry areas. In addition, moulds can be highly hygroscopic due to their large surface area. The result is that water molecules are filtered directly from the air. This process is particularly enhanced when mould develops on cold walls.一旦形成有利的条件，有些霉菌可以将游离水运输到干燥的区域。另外，霉菌的表面积较大，具有很高的吸湿性。因而它们能直接从空气中滤吸水分子。一旦霉菌在冷壁上滋生，这一过程会进一步增强。

Fig 2. Effect of temperature on mould growth图2温度对霉菌生长的影响

Source: http://www.ibp.fraunhofer.de/content/dam/ibp/de/documents/Publikationen/Fachzeitschriften/mold_growth_predictiontcm45-35017.pdf资料来源：http://www.ibp.fraunhofer.de/content/dam/ibp/de/documents/Publikationen/Fachzeitschriften/mold_growth_predictiontcm45-35017.pdf

Whereas reducing relative humidity shows a marked reduction in the probability of mould growth, changes in temperature has a less drastic effect, particularly when taking into account the preferred comfort range of 20°C / 68°F to 25°C / 77°F for human operators in manufacturing and storage areas.降低相对湿度能够显著降低霉菌滋生的可能性，但温度变化的影响却相对较低，尤其是当生产和存储区域的操作工人的首选舒适温度范围是在20℃至25℃时。

The figures shown are previously are generalisations of mould growth to allow some visualisation of the potential problems. The actual characteristics for each type of mould are different. Some examples are shown in Fig 3. and 4.之前的数据说明霉菌经过多代繁殖才会显现出一些潜在的问题。各种霉菌的具体特点也各不相同。具体示例请参见图3和图4。

Fig 3. Isopleths of growth rate and germination for Aspergillus restrictus
图3局限曲霉生长速率和萌芽的等值线

Fig 4. Isopleths of growth rate for Aspergillus ruber & Stachybotrys chartarum
图4赤曲霉和葡萄穗霉生长速率的等值线图

Source: http://www.ibp.fraunhofer.de/content/dam/ibp/de/documents/Publikationen/Fachzeitschriften/mold_growth_predictiontcm45-35017.pdf资料来源：http://www.ibp.fraunhofer.de/content/dam/ibp/de/documents/Publikationen/Fachzeitschriften/mold_growth_predictiontcm45-35017.pdf

While the information in Figures 1 and 2 present general, worst-case growth probability, Figures 3 and 4 show that the 3 types of mould selected do not approach these general growth and germination levels. Therefore, using a worst-case approach will ensure that the majority of mould growth stops at a sufficiently low relative humidity level.虽然图1和图2展示了一般霉菌生长的可能性（最坏情况），但图3和图4却显示，所选的3种霉菌并没有达到这些一般的生长和萌芽水平。因此，使用最坏情况的方法能够确保，如果相对湿度足够低，绝大多数霉菌的生长都会受到抑制。

Building materials can also play a part in the growth and germination times, in general materials that are prone to storing moisture (e.g. wallpaper, fabrics) will provide a better substrate for microbial growth.建筑材料也在霉菌的生长和萌芽期起到重要的作用，一般而言，易潮的材料（比如壁纸、织物）是细菌滋生的良好基质。

Micro-organisms in ambient conditions外界条件中的微生物

Moisture is essential for microbes to grow, so be aware of any potential sources of water vapour in the manufacturing area:水分对于微生物的生长至关重要，所以要留意生产内任何可能产生水蒸汽的地方：

From the air / water vapour空气/水蒸气中

Ingression进浸

Construction moisture建筑湿度

Cleaning processes清洗过程

Product and production process产品和生产工艺

By-product of combustion (gas heating, engines)燃烧副产物（燃气供热、发动机）

Packaging包装

Raw materials原材料

Production staff生产人员

Excess moisture due to insufficient heating and ventilation由于加热和通风不良造成湿度过高

Bad insulation, especially in the area of thermal bridges隔热差，尤其是在热桥区

Accidents and unplanned incidences e.g. Spillages意外事故，比如溢漏

Leaks泄漏

Extreme weather极端气候

Mould growth happens anywhere when there is moisture and a food source available, and often this takes place in hard to reach places:只要有水分和食物来源，任何地方都会滋生霉菌，而且往往是在难以清洁的位置：

Cold water piping behind equipment, cabinets or partitions设备、柜子或隔板后面的冷水管

Air handling ductwork with either 70%+ relative humidity or water droplets caused by excessive cooling相对湿度达到70%以上或者因过冷形成水滴的空气处理管道系统

Under plant and storage equipment装置和存储设备下方

In clumps of dirt, dust and waste that might accumulate out of sight在看不到的地方堆积的污垢、灰尘和废弃物中

In ceiling tiles天花板中

On exterior walls and doors外墙和门上

Around windows窗户周围

In general, ambient or treated air above 50% relative humidity will allow some level of microbial growth to take place. Condensation on cold surfaces will increase this growth.一般而言，环境空气或处理后的空气的相对湿度高于50%，就会滋生一定的微生物。冷表面上的冷凝也会促使微生物生长。

Fig 5: Probability of mould growth as relative humidity changes
图5：霉菌生长相对于相对湿度变化的概率

Humidity control that reduces the relative humidity below 50% will stop all microbial growth. Higher relative humidity levels (up to 70%) will slow growth, and this may be acceptable depending on the local environment, product being produced, cleaning processes, etc. Temperature control alone is not sufficient as some microbes are specialised to survive temperature extremes. It should be noted that dehumidification and normal air treatment will not remove existing microbes or spores in the environment – that problem will always be present. Using appropriate filters will reduce the amount of spores leaving the air handling system:若湿度控制能将相对湿度控制在50%以下，那么所有微生物的生长都会受到抑制。较高的相对湿度（高达70%）会降低微生物的生长速度，但是根据当地环境、所生产的产品、清洁工艺等，也可以接受较高的相对湿度。单纯控制温度是不够的，因为有些微生物能在极端温度下生存。应当注意，除湿和正常的空气处理不会去除环境中现有的细菌或孢子——细菌滋生问题将继续存在。使用适当的过滤器将降低空气处理系统中残留的孢子量：

Fig 6: Sizes of common outdoor airborne particles

图6：常见室外空气颗粒的粒径

Fig 7: Filter types and their effectiveness against varying particle sizes
图7：过滤器类型及其对于滤除不同粒径颗粒的有效性

Chilled Stores (Above 0°C / 32°F)冷藏（高于0℃/32℉）

There are particular challenges with chilled stores in the 2 to 8°C / 35 to 46 °F temperature range. If humidity is not controlled then relative humidity within the chilled space can be >90%. Cold surfaces will allow condensation to occur and if this condensation is left untreated additional issues can arise. For example, in chilled spaces water droplets will tend to form on the lighting fittings and ceiling near the fan outlet of the chiller units, as well as on the chiller units themselves. These droplets occasionally drop, and these drops have the potential to carry any mould, bacteria or yeast growths present from the ceiling to surfaces below, resulting in a potential cross contamination problem. Luckily, this is easy to treat with humidity control.尤其是在2至8℃/35至46℉的温度范围内冷藏时，会遇到微生物滋生的难题。如果没有控制湿度，那么冷藏空间中的相对湿度会超过90%。冷表面会发生冷凝，如果置之不理，会引发其它的问题。比如，在冷藏空间中，照明装置和制冷装置风扇出口附近的顶板以及制冷装置上会形成水滴。这些水珠偶尔会滴下，而水滴可能会把顶板上滋生的任何霉菌、细菌或酵母菌携带至滴落表面上，从而导致交叉污染。庆幸的是，使用湿度控制可以很容易地解决这一问题。

Conclusion结论

With over 60 years of experience in the field of humidity control, Munters has a range of solutions to control microbial growth by reducing the relative humidity level in any size of production or storage facility. Humidity control is a valuable addition to commonly used cleaning strategies for maintaining aseptic and non-aseptic working areas, and should be considered at the design phase of any new facility. It can also benefit existing facilities that are experiencing any of the problems described above, and also be deployed when changes to the moisture load within the manufacturing or storage area occur as a result of increased production, changes to building ventilation or external environment.蒙特在湿度控制领域拥有60多年的丰富经验，已经推出了一系列的解决方案，在任何规模的生产或存储设施中，均可通过降低相对湿度抑制微生物的生长。湿度控制是保持无菌和非无菌工作区清洁的另一种有效的常用方法，应当在任何新设施的设计阶段加以考虑。出现任何上述问题的现有设施也可以通过这种方法加以处理，当生产增加、建筑通风或外部环境发生变化，从而导致生产或存储区内会发生湿度变化时，也可以采用湿度控制。