Contamination control

Contamination control (IPA: /kənˌtæməˈneɪʃən kənˈtroʊl/) is the collective name for any method that effectively controls the growth and proliferation of contamination. Contamination control may refer both to contamination prevention as well as to decontamination (i.e. controlling the spread of contamination from a hazardous materials site, etc.).

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Contamination control measures at a premier lens manufacturer (Carl Zeiss.)

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Flooring in a material handling area at Pharmaceutical company Lilly, France.

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Gowning area at Alcatel, London, UK.

Function

Contamination control is one of the most vital aspects of health and safety in areas where environmental sterility is a critical concern. The purpose of the wide range of contamination control procedures and standards is to ensure cleanliness by reducing or eradicating all viable and non-viable contamination, and maintaining an efficient rate of production.

Where is contamination control used?

One of the most common environments that incorporates contamination control into its standards protocol is the cleanroom. There are many preventative procedures in place within the cleanroom environment. Procedures include subjecting cleanroom staff to strict clothing regulations, and there is often a gowning room where the staff can change under sterile conditions, so as to prevent any particulate from entering from the outside environment. Certain areas in the cleanroom have more stringent measures than others. Places such as packaging areas, corridors, gowning rooms and transfer hatches incorporate strict contamination control measures in order to keep to the cleanroom standards.

Contamination control is also an important asset to laboratories in industries such as the pharmaceutical and life science sectors. Other places of use include automotive paint shops, entrances to industrial kitchens and food service providers, many manufacturing areas, and in electronic component assembly areas.

More recently contamination control has been a concern for laboratories and other sensitive environments as an effective bio-security crisis management measure. Some banks and insurance companies use contamination control products as part of their disaster management protocols. Preventative measures are put in place as preparation for potential pandemics or the proliferation of biohazards in any potential terrorist attack.

Types of contamination

There are many types of organism that are potentially detrimental to processes in a critical environment. Seven of the most common contaminants are:

• Aspergillus niger
  
• Clostridium difficile
  
• Escherichia coli
  
• Methicillin Resistant Staphylococcus aureus (MRSA)
  
• Pseudomonas aeruginosa
  
• Pseudomonas cepacia
  
• Salmonella enteritidis
  

These, and many other damaging contaminants can infiltrate critical areas in a manner of ways. Particulate can enter by air, foot, or on any carrier between the external environment and inside the critical area.

The effects of contamination.

Contamination poses a significant risk to businesses as well as the individual. Unguarded proliferation of contamination can quickly lead to product damage, yield reduction, product recalls and other outcomes highly detrimental to businesses. A number of products over a range of industries are recalled due to ineffective contamination control systems.

By this evidence it could be argued that many businesses are not adequately protecting themselves from the harmful effects of contamination, and many products over many industries are being recalled due to unsafe manufacturing processes.

Is this really an acceptable attitude and policy from one of the government agencies responsible for the safety of the nation’s food supply? Where is the public outrage and demand for accountability? Perhaps the pointless prattling of politicians and of the television media’s “blabberatzi” has simply immunised us all from any reaction to the flagrant government agency unresponsiveness and blatant incompetence. It must be so, since years and years of recalls and years and years of studies, renewed attention, promises, and platitudes have left us with the same results.

Types of contamination control

Body movement causes contamination and protective clothing such as hats, cleanroom suits and face masks are basic forms of contamination control. Apart from people, the other common way for contamination to enter is on the wheels of trolleys used to transport equipment.

To prevent airborne contamination, high efficiency particulate air (HEPA) filters, airlocks and cleanroom suits are used. HEPA filtration systems used in the medical sector incorporate high-energy ultra-violet light units to kill off the live bacteria and viruses trapped by the filter media. These measures restrict the number of particulates within the atmosphere, and inhibit growth in those that are viable.

Studies by 3M show that over 80% of contamination enters the cleanroom through entrances and exits, mostly at or near floor level. To combat this suitable flooring systems are used that effectively attract, retain and inhibit growth of viable organisms. Studies show that the most effective type of flooring system is one of polymer composition.

Polymer mats are particularly effective due to their suppleness as they allow for more contact with serration on shoes and wheels and can accommodate for more particles whilst remaining effective. An electrostatic potential adds to the effectiveness of this type of contamination control as it holds particles until being cleaned. This method of attracting and retaining particles is more effective than mats with an active adhesive coating which needs to be peeled and is often not as supple. As long as the tack level of the mat is greater than the donor (foot or wheel), the contamination touching the surface will be removed. Very high tack surfaces pose a contamination threat because they are prone to pulling off over-shoe protection. Polymeric flooring is produced to ensure a higher level of tackiness than the surfaces it comes into contact with, without causing discomfort and potentially damaging ‘stickiness’.

See also

• Cleanroom
• HEPA
• Decontamination