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Contamination and Cross-contamination in Manufacturing

The term Contamination and Cross-contamination is used in pharmaceutical industries when products undesirably come in contact or are mixed with others products or their parts. Contamination may be in starting material or a product by other related products. The risk of accidental contamination may arise from the uncontrolled release of dust, gases, particle vapor, spray, organism, in-process Products in the area, residue on the equipment/operator cloth, and skin. The significance of the contamination risk varies with the type of contaminants and the Product being contaminated.

In this article, we will learn about contaminants and types of contamination, and cross-contamination in pharmaceutical manufacturing sites. Let’s begin with the definition, types of contaminants, contamination, and cross-contamination.

Definition of Contaminants and Contamination with Examples

Contaminants: Contaminants may be an impurity, Products, or substances that are unrelated to a product that is being manufactured likes; Foreign products, Particulate matter, Microorganisms, Endotoxin (degrade microorganisms), Cross-contamination of products may also cause contamination.

The People/machine-generated contaminant:

  1. The human outer skin is completely shed every 24 hours.
  2. Particles of 0.3 microns and greater are liberated at a rate varying between 100000 to 10 million per minute.
  3. A person while walking will liberate thousands of bacteria per minute, and a single sneeze can produce up to 1 million bacteria.
  4. The manufacturing process itself can generate contaminants, for example, paint from equipment, dust from belt drives, etc.

Contamination: Contamination is an undesirable introduction of chemicals, microbial nature substances, or foreign matter into or onto a starting material/intermediate, during production, sampling, packaging/repackaging, storage, and transport.

Types of contamination:

  • Chemical contamination (leftover residue of the previous process)
  • Microbiological contamination ( microbiological flora)
  • Particulate contamination ( particles like dust, fibers, oil, or grease from the pieces of equipment. others like haires, and skin fragments.)
Table showing Contamination and Cross-contamination along with its source


Cross-contamination is the contamination of the starting, intermediate products, or finished products with other starting materials or products during production.

Source of cross-contamination generate?

  1. It may be due to poor design and operation of air handling systems and dust extraction systems.
  2. Inadequate procedure for personnel and equipment
  3. Not proper cleaning of equipment.

How to minimize cross-contamination?

  • cross-contamination may minimize by using closed production systems
  • Applying a validated cleaning procedure
  • By maintaining a level of a product that is being manufactured
  • Adequate premises
  • Installing correct air pressure Airlock types systems likes; Cascade airlock

Way to control dust in pharmaceuticals: 

Dust control is very necessary to control contamination and cross-contamination in pharmaceutical manufacturing areas. Whenever possible, the dust or vapor contaminants should be removed immediately by knowing their source.

Dust extraction duct should be designed with sufficient transfer velocity to ensure dust is carried away. Airflow direction should be carefully chosen so that the operator does not contaminate the Product. Use of well-validated HEPA filters in series to provide additional protection. A sophisticated computer-based data monitoring system may be installed.


The system or equipment shall be validated to prevent the Product from contamination and cross-contamination. Cleaning validation of equipment and area with a well-defined procedure shall be maintained. Using the cleaning validation approach, we can easily identify any discrepancies or loops in a system.

Pharmaceutical manufacturers are required to the validated cleaning procedure, AHU system, air cascade, and personnel movements to ensure the production of good quality products throughout their life cycle. Failure to prevent contamination and cross-contamination can lead to a loss in customer faith or satisfaction from the investors, loss of market values, loss in money, and direct consequences from regulatory bodies.

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