Microbiological Testing for Natural Health Products

Natural health products can vary significantly in formulation, ingredients, dosage form, and manufacturing process. These differences can influence both the risk of chemical and microbial contamination present in a Finished Product.

PPB Analytical offers a broad range of testing services for NHP companies by offering a broad range of testing services. Over the next four posts, we’ll present more details to highlight the various testing categories.

Today, let’s talk about the various tests available for Microbiology and how they can support an effective testing program.

Why Microbiological Testing Is Critical for NHP Quality and Safety 

Microorganisms can be introduced through raw materials, water, manufacturing environments, processing, handling, packaging, or storage.

This can be particularly relevant for products containing botanical, agricultural, or minimally processed ingredients, which may naturally carry microorganisms before entering the manufacturing process.

Microbiological testing helps quality teams assess whether a finished product meets its established microbial specifications. Health Canada’s Quality of Natural Health Products Guide identifies microbial contaminants as an important component of finished-product specifications, including organisms such as Salmonella, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, as well as total aerobic counts and yeast and mould.

Testing does not replace good manufacturing controls; it verifies the microbiological quality of the finished product.

Common Tests for Microbiology

Total Plate Count

Total Plate Count, often reported as Total Aerobic Microbial Count (TAMC), provides a general measure of the viable aerobic microorganisms present in a sample. Rather than targeting one specific organism, it provides an indication of the product’s overall aerobic microbial load.

For conventional non-aqueous oral preparations such as many tablets, capsules, and chewables, the commonly referenced USP acceptance criterion for TAMC is 10³ CFU/g or mL. The applicable Finished Product Specification should always be confirmed for the specific NHP, as different limits may apply depending on the ingredients and dosage form.

At PPB Analytical, the current reporting detection limit for Total Aerobic Microbial Count is <5 CFU/g.

Yeast and Mould

Yeast and mould testing focuses on fungal microorganisms. These organisms are abundant in the natural environment and can be particularly relevant for products containing botanical or agricultural ingredients that may be exposed to microorganisms during growing, harvesting, transportation, processing, or storage.

For conventional non-aqueous oral preparations, the commonly referenced USP acceptance criterion for Total Combined Yeasts and Moulds Count (TYMC) is 10² CFU/g or mL. The applicable limit may differ for certain botanical, herbal, probiotic, or other specialized products.

At PPB Analytical, the current reporting detection limit for Total Combined Yeasts and Moulds is <5 CFU/g.

E. coli

Escherichia coli is a Gram-negative bacterium that can be used as an indicator of fecal contamination and inadequate sanitary control. Its presence in an NHP can indicate contamination during processing, handling, or manufacturing. E. Coli, when present, can lead to food poisoning, so it is critically important to test the final dosage form and confirm absence.

The pass criteria is proof of absence in a specified amount of material. For conventional non-aqueous oral preparations, USP <1111> specifies that E. coli should be absent in 1 g or 1 mL. PPB is equipped to handle tests supporting multiple pharmacopeia standards. 

Salmonella

Salmonella is a group of pathogenic bacteria that can cause gastrointestinal illness and represents a significant microbiological safety concern when present in products intended for oral consumption. Salmonella, when present, can lead to food poisoning, so it is critically important to test the final dosage form and confirm absence.

The pass criteria is proof of absence in a specified amount of material and is often more strict than even E. coli testing. PPB is equipped to handle tests supporting multiple pharmacopeia standards, including Salmonella as absent in 25 g. 

Staphylococcus aureus

Staphylococcus aureus is a bacterium commonly found on human skin and in the environment that can be introduced through handling, personnel, processing environments, or contaminated materials. S. aureus, when present, can cause skin infections, wound infections, and other illnesses, so it is important to test the final dosage form where required and confirm absence.

The pass criteria is proof of absence in a specified amount of material and depends on the applicable pharmacopeial standard and Finished Product Specification. For orally ingested solid NHPs such as tablets and chewables, S. aureus is not a universal USP <1111> specified-organism requirement. PPB is equipped to handle tests supporting multiple pharmacopeia standards and product-specific specifications.

Pseudomonas aeruginosa

Pseudomonas aeruginosa is an environmental bacterium commonly associated with water and moist environments and can be introduced through contaminated water, materials, or processing environments. P. aeruginosa when present, can cause infections, particularly when it enters damaged tissue or affects individuals who are more susceptible to infection, so it is important to test the final dosage form where required and confirm absence.

The pass criteria is proof of absence in a specified amount of material and depends on the applicable pharmacopeial standard and Finished Product Specification. For certain liquid NHPs, Health Canada identifies P. aeruginosa as a specified microorganism, while it is not a universal USP <1111> requirement for solid oral NHPs. PPB is equipped to handle tests supporting multiple pharmacopeia standards and product-specific specifications.

Choosing the Right Microbiological Testing

Testing requirements can be influenced by formulation, dosage form, ingredients, raw materials, manufacturing process, intended use, and finished-product specifications.

Providing your laboratory with complete product and specification information helps ensure the testing request is appropriate for the product being analyzed.

PPB Analytical offers testing for Total Plate Count, Yeast and Mold, E. coli, Salmonella, Staphylococcus aureus, Pseudomonas aeruginosa, and bile-tolerant Gram-negative bacteria, among others.

See our full list of NHP testing services here

Let’s Talk Testing

Whether you’re developing a new natural health product, reviewing your microbiological specifications, or strengthening your current testing program, we’re here to help.

Have a microbiology question? Connect with the PPB Analytical team to discuss your product and testing requirements