Challenge Testing

Challenge testing is an internationally recognised test method used to assess what happens when a food is contaminated during its shelf life. It consists of inoculating the food with targeted pathogens or spoilage micro-organisms under controlled experimental conditions.

Challenge tests performed in the laboratory can help ensure the microbiological quality and safety of your products. This experimental technique consists in inoculating a known concentration of a microorganism into a product and following its development through the use of a specific protocol.

Mérieux NutriSciences AQ runs several types of Challenge Studies with the most common being “Pathogen Growth Inhibition Studies” and “Pathogen Inactivation Studies”. To determine if these tests are suitable for a food product, Mérieux NutriSciences AQ first checks water activity and pH level. These would determine if there is any chance of organisms (and which organisms precisely) will have growth in the food products. 

For example, if a food product has water activity of less than 0.88 aw, then no pathogen can grow in this food product despite the pH level. Note, there can still be pathogens present but cannot have growth. Another example would be if a product has water activity of between 0.88 and 0.90 aw, then the product can have pathogen growth of Staphylococcus aureus if the pH level is more than 5.0.

Pathogen Growth Inhibition Studies involve food products being challenged against a certain bacterial pathogen, to determine if the specific type of food processing and packaging involved can inhibit the growth of the pathogen.

Pathogen Inactivation Studies involve challenging the food products against a certain bacterial pathogen to determine if certain formulations in the food can inactivate the pathogen. Combined studies of these can also be done if requested by the clients. These studies can be impacted by the storage and packaging conditions of the food.

Why do you need a food challenge test?

• Challenge studies are useful to understand safety or spoilage risks in a food product.
• Challenge tests are needed when you must assess a product’s preservative effects.
• This test might be needed during the safety assessment of food products in the absence of a killing step.

Our challenge testing services offer the following benefits:

• Evidence of spoilage organism containment by intrinsic product factors
• Classification of products according to the pathogen growth risk
• Evaluation of risks and determination of critical points within the HACCP approach
• Determination of criteria for acceptable levels of pathogenic indicator organisms

For any further enquiries and challenge testing requests, please contact our sales team below.