What is Microbial Limit Test? Microbial contamination Types, Measures & Sources

What is Microbial contamination?

Microbial contamination refers to the presence of harmful and infectious microorganisms, viz. bacteria, fungi or virus, in a material, substance or environment, where they are not intended to be or in amounts that exceed normal levels. Microbial contamination is an everlasting problem for Pharma, Cosmetic, Ayurveda, Herbal and Food manufacturers worldwide.

It can be introduced to an environment or product through a variety of sources, including human contact, contaminated equipment or raw material, and environmental factors such as air or water. Once introduced, these microorganisms can grow and reproduce rapidly, potentially leading to illness or other harmful effects.

In case of medicines, Microbial contamination can result in drug degradation by breaking down the active ingredients thereby affecting the potency, stability and efficacy of the product. Moreover, the presence of pathogens poses a serious health threat to consumers, especially those who are already ill or are having a weakened immunity. Some microorganisms can produce harmful microbial toxins which can cause severe harm to patient and even death.

Microbial contamination in the pharmaceutical, food and cosmetic industry. WHO has also published guidelines by providing recommendations for manufacturing process, storage and testing. WHO emphasizes the importance of Good Manufacturing Practices (GMP) and also advocates regular monitoring and testing for Microbial contamination in manufacturing environment, raw materials, and finished products.

Microbial contamination can lead to various type of toxicity depending on the type of microorganism involved and the mode of contamination. Some examples are as follows:

• Food poisoning: Contamination of food by bacteria viz. Salmonella, Campylobacter, and Escherichia coli can cause symptoms such as vomiting, diarrhoea, and abdominal pain.
• Escherichia coli infection: An illness caused by the bacterium Escherichia coli, which can produce toxins that cause bloody diarrhoea, abdominal cramps, and kidney failure.
  
• Botulism: Contamination of products by the bacterium Clostridium botulinum can lead to the production of botulinum toxin, which can cause paralysis and even death.
  
• Cholera: Infection with the bacterium Vibrio cholerae can lead to cholera, which can cause severe diarrhoea and dehydration.
  
• Staphylococcal food poisoning: An illness caused by consuming food contaminated with Staphylococcus aureus, which can produce enterotoxins that cause nausea, vomiting, diarrhoea, and stomach cramps.
  
• Salmonellosis: An illness caused by consuming food contaminated with Salmonella bacteria, which can cause diarrhoea, fever, and abdominal cramps.
  
• Toxic shock syndrome: A potentially life-threatening illness caused by toxins produced by certain strains of Staphylococcus aureus or Streptococcus pyogenes, which can cause fever, rash, low blood pressure, and organ failure.
  
• Fungal infections: Contamination by certain types of fungi such as Aspergillus fumigatus and Candida albicans can lead to fungal infections, which can cause a range of symptoms depending on the location of the infection. Contaminated cosmetic products can support the growth of fungi, which can lead to fungal infections such as ringworm or athlete’s foot.
  
• Skin irritation and allergic reactions: Some microorganisms can cause skin irritation, redness, itching, and allergic reactions when applied to the skin. For example, Staphylococcus aureus and Pseudomonas aeruginosa can cause skin infections and rashes.
  
• Eye infections: Microbial contamination can cause eye infections when cosmetics come into contact with the eyes. For example, Pseudomonas aeruginosa is a common cause of eye infections in people who wear contact lenses.
  
• Acne: Microbial contaminated cosmetics or skin products can contribute to the development of acne and other skin blemishes.
  

The common measures to control Microbial contamination are as mentioned below:

• Good Manufacturing Practices (GMPs): GMPs are guidelines and regulations that ensure that products are consistently produced and controlled according to quality standards. This includes using sterile equipment and containers, testing raw materials for contaminants, and ensuring proper storage conditions.
  
• Good Agricultural and Collection Practices (GACPs): GACPs are guidelines that ensure the quality and safety of herbal raw materials. They cover all aspects of production, from planting and harvesting to processing and storage.
  
• Good Hygienic Practices (GHPs): GHPs are guidelines that ensure the cleanliness and hygiene of products during processing and storage. They cover all aspects of production, from cleaning and sanitation to pest control and waste management.
  
• Monitoring and testing: Regular monitoring and testing of products can help to identify and address any Microbial contamination issues before they become a problem. This can include testing raw materials and finished products for contaminants, as well as regularly monitoring the manufacturing environment for potential sources of contamination.
  
• HACCP (Hazard Analysis and Critical Control Points): HACCP is a systematic approach to identifying and controlling hazards in the production process. This includes identifying potential Microbial contamination points, monitoring and testing to detect any contamination, and implementing control measures to prevent contamination.
  
• Use of appropriate packaging: Appropriate packaging can help to prevent Microbial contamination by providing a barrier to outside sources of contamination. This can include using airtight and moisture-resistant packaging.

Microbial contamination can occur from a variety of sources, including:

• Raw materials: At times the raw materials can be contaminated with microorganisms, which can then contaminate the final product.
  
• Equipment: Equipment and utensils that are not properly cleaned and sanitized can be a source of contamination.
  
• Environmental sources: Microorganisms can be present in soil, water, air, and other environmental sources. Contamination can occur when material or surfaces come into contact with these sources.
  
• People: Human carriers of microorganisms can contaminate food and surfaces through improper hygiene practices, such as not washing their hands thoroughly or not covering their mouths when coughing or sneezing.
  
• Cross-contamination: This occurs when microorganisms from one material or surface are transferred to another material or surface, either directly or indirectly.
  
• Improper storage: Improperly stored product or material can become contaminated with microorganisms that can grow and multiply over time.
  
• Processing and handling: Improper processing and handling of finished products can also lead to Microbial contamination, such as when food is not cooked to the appropriate temperature or is stored at the wrong temperature.

In India, the various Government agencies responsible for establishing guidelines and regulations to prevent Microbial contamination in various sectors such as Food, Water, Pharmaceuticals, Ayurveda, Herbal medicines and extracts are,

The permissible limit of Microbial contamination (as per Indian Pharmacopoeia) is as follows:

The permissible limit of Microbial contamination (as per Indian Pharmacopoeia) is as follows:

• Total Plate Count: 10³
  
• Total Yeast and Mould Count: 10²
  
• Bile Tolerance Negative Bacteria: 10²
• Escherichia coli: Absent
  
• Salmonella species: Absent
  
• Shigella: Absent

The permissible limit of Microbial contamination (as per the Ministry of AYUSH) is as follows:

• Total Plate Count: 10⁵
  
• Total Yeast and Mould Count: 10³
  
• Staphylococcus aureus: Absent
  
• Escherichia coli: Absent
  
• Pseudomonas aeruginosa: Absent
  
• Salmonella species: Absent
  

• Plant and animal-origin raw materials
  
• Herbal and Ayurvedic medicines
  
• Herbal extracts
  
• Cosmetics
  
• Food and Nutraceuticals
  
• Pharma products and Excipients
  
• Water
  
• Soil
  

Microbial Limit Test (MLT) is an essential Quality control test in the Pharmaceutical, Ayurveda, Herbal, Food and Cosmetic industry, as it helps to ensure the safety and efficacy of finished products by detecting and controlling Microbial contamination. This test is used to determine the number of viable microorganisms present in a sample.

In India, Indian Pharmacopoeia and Ayurvedic Pharmacopoeia provides guidelines for performing the MLT as well as specifies the acceptable limits for Microbial contamination in pharmaceutical products, which may vary depending on the type of product and it’s intended use. It is performed on raw materials, finished products, and the manufacturing environment.

Overall, MLT is an essential Quality control test in the food, pharmaceutical and cosmetic industry in India, and it helps to ensure the safety and efficacy of products by detecting and controlling microbial contamination.