Challenge Testing & Process Validation

Using our in-house expertise in processing, product development and evaluation, we can model your process parameters and provide you with a real-time evaluation and verification of your test conditions and product safety.

Perfecting product and process validation

Challenge testing

The process of challenge testing involves inoculating a food product with a known concentration of a particular ‘risk’ microorganism to see what happens to it during production, processing, distribution or subsequent handling by the consumer. It is the ultimate evidence of the safety of a food product or process.

We use challenge testing to:

  • Determine a product’s safety and stability during storage through to consumption
  • Establish a product’s shelf life
  • Aid product formulation in terms of intrinsic control factors (e.g. pH and water activity)
  • Establish critical points in a processing line (measuring process control factors such as temperature and time)

Case studies

  • Evaluate the growth of Listeria monocytogenes in ready-to-eat products
  • Establish the effect of different modified atmosphere mixtures on the growth of pathogenic and spoilage organisms
  • Determine the effect of salt and vinegar on survival of Bacillus spp. during baking and shelf life in bread
  • Determine the effect of product reformulation and sugar reduction on the growth of pathogens in dairy products

Product/process validation

Change can be either external (e.g. salt reduction) or internal (e.g. replacement of ingredient to lower costs) but its consequences are not always obvious. For example, reduction of salt may give a similar taste but it may also diminish its protective effect against microorganisms, and cause more spoilage or even foodborne disease.

That’s why our expert service allows companies to validate and optimise their processing conditions, and to quantify the impact on:

  • Food safety
  • Quality
  • Stability and sensory properties of foods

We use product/process validation to:

  • Determine microbial survival rates and microbial inactivation kinetics
  • Validate processing conditions on laboratory and pilot plant scale
  • Optimise processes and verify efficacy, covering safety, quality, stability, sensory and nutritional attributes
  • Investigate new materials and technologies for food packaging and processing

Case studies

  • Determine a safe pasteurisation process for a milk-based beverage
  • Confirm the lethality of a heat process in beverages
  • Investigate the effect of baking and alternative preservatives on germination and growth of Bacillus spp. in bread
  • Evaluate the survival rates of E. coli in beef burgers during cooking