Food Testing - Challenge Testing

CHALLENGE TESTING :

What is it?
A positive challenge of the microbial stability of both product and production process.

How is it performed?
The product is inoculated with a cocktail of stress-conditioned microorganisms selected by predictive microbial risk assessment. Sub lethal stress conditioning develops the inherent strength and stability of the organisms such that they survive introduction to the new environment and provide the most robust challenge. The microbial tests performed at regular intervals are customised to detect those microorganisms present in the inoculum.

When do you do it?
At NPD stage to establish shelf life for new products or to extend shelf life of existing products. Especially useful if time constraints prohibit evaluation across entire target shelf life.

Pros
Provides robust information to complete a microbial risk assessment. Not often required to last for the full duration of target shelf life. The likely period over which growth and death would be seen can be estimated as part of the predictive microbial risk assessment and meaningful evaluations obtained which when extrapolated negate any requirement for impractical lengthy assessments.

Cons
Negative controls are required. These can however double up as shelf life validating tests.