GMP Primer: Contamination Control Training
How much do the employees in your organization know about keeping contaminants out of manufacturing processes? If you want to give all of them a basic grounding in contamination control, follow this outline for your next training session.
Part One: Contamination Control Definitions
Start by defining the term as all activities conducted to control the existence, growth and proliferation of contaminants. Those activities apply to atmosphere as well as surfaces and include decontamination as well as prevention.
Contaminant can be defined as any substance that should not be present, no matter how minor. Micro-contaminant refers to any solid small enough to be measured in microns, which equal 1,000th of a millimeter.
The three types of contaminants are:
- Chemical – nonliving compounds or substances, including residue from chemicals used in cleaning products;
- Particulate – nonliving particles, such as dead skin or hair, and live organisms, such as airborne bacteria; and
- Microbial – a subset of particulate contaminants consisting of bacteria, fungi, molds, yeasts, mycoplasma, protozoa and viruses.
All contaminants are undesirable and can affect the quality or viability of a product, but two classes present serious risks. Pathogens are infectious microbes that may cause disease and illness, while endotoxins are natural compounds found inside pathogens, such as bacteria, that are not viable on their own. Exposure to endotoxins can result in fever, shock or death.
Contamination can occur in three ways:
- Dispersion, in which airborne contaminants settle on sterile materials or products;
- Cross-contamination, in which materials, tools or other contaminated product touch sterile materials or product; and
- Ineffective sterilization or cleaning, in which existing contaminants are not removed or neutralized.
Part Two: Methods of Control
Clean air, cleanrooms and associated controlled environments are the primary weapons against contamination.
Filters and air locks are used to remove existing contaminants from the air and keep contaminated air from entering the sterile area. High-Efficiency Particulate Air (HEPA) filters remove 99.7 percent of particles larger than 0.3 microns.
Air locks consist of a space with two doors equipped with HEPA filters to prevent contaminants from reaching sterile areas. These areas are commonly used for gowning and equipment transfer.
The next level of defense is the cleanroom, which utilizes Ultra Pure Air filters that remove particles as small as 0.1 microns. In a cleanroom, surfaces must be hard, durable, easily cleaned and rust resistant. Stainless steel and plastic equipment are commonly used because they can withstand cleaning, disinfecting and sterilizing.
Another barrier to contamination is air pressure differential, which is used to control the flow of air from one area to another. Increased air pressure in a cleanroom keeps outside air from entering.
Laminar airflow systems move an entire body of air along parallel flow lines at uniform velocity. This flow picks up particles from work surfaces and people along its way and carries it out of the sterile area for recycling.
Part Three: Cleanroom Apparel
Employees working in a cleanroom wear special clothing designed to prevent transfer into sterile areas of outside contaminants, including skin particles, liquids and mouth/nose-driven contaminants. The purpose of cleanroom apparel is to protect the purity of the product, not the safety of the wearer.
The donning of cleanroom apparel, known as “gowning,” varies according to the level of sterility required. The maximum level of gowning consists of:
- A hood with shoulder cape;
- A one- or two-piece coverall tightly closed at the wrists and ankles with a closed collar into which the shoulder cape is tucked;
- High boots;
- A mask or self-contained air system; and
- Gloves suitable to the task that cover the body garment’s wrist closures.
In areas with less stringent requirements, the hood may be replaced by a hairnet or other head cover, and a coat or frock instead of a body garment. Footwear may feature overshoes or shoe covers. This apparel is often disposable and used mostly in construction or maintenance phases.
Part Four: Personnel Responsibilities
Cleanroom workers must follow specific procedures and behaviors to prevent contamination. Access to the cleanroom is strictly controlled. In addition to following proper gowning procedures, workers are directed to move slowly and purposefully to avoid creating turbulence.
Proper hygiene for cleanroom workers includes regular bathing, neat and clean hair, thoroughly washed hands and trimmed finger nails.
Certain personal items are prohibited in the cleanroom, including:
- Wrist watches and jewelry;
- Talc and face powders, deodorant, aftershave and, usually, cosmetics; and
- Gum, food, beverages and cigarettes.
In next week’s issue, we’ll continue the discussion of contamination control, covering the topics of cleaning, disinfecting, sterilization, and storage and usage of material, equipment and finished products.
The complete Contamination Control training package, including slides, leader’s script and knowledge assessment, is available as part of the FDAnews Customizable Training Series for drug manufacturers and devicemakers.