In-Plant Validation Studies

Microbial Process Validation

Microbial Process Validation consists in validating with scientific information that a process is capable of effectively mitigating a microbial hazard of concern. The ability of a process to inactivate a target pathogen is usually measured by the log reduction of the pathogen in a target product. For instance, a 5-log reduction of Salmonella in spices, nuts, flour, etc. using a thermal process. Process validation is a cornerstone of the major international Food Safety Standards & Regulations.

Conducting a proper validation project usually requires using a combination of scientific methods, which can be categorized in 3 groups:

  • Literature review
  • Mathematical modeling
  • Experimental trials at lab, pilot- and plant-scale

In-Plant Validation Studies are usually considered as a “gold standard” for they provide real-life data of a process efficacy.


In-Plant Validation Studies with Surrogate Microorganisms

Since the use of pathogenic microorganism in processing facilities is not advised, surrogate microorganisms are used as test organisms for in-plant validation studies. Surrogates are non-pathogenic microorganisms that mimic the resistance of foodborne pathogens under different kinds of stress (heat, chemical, …).

Due to their safety, surrogates are used directly at the plant to test the efficacy of microbial kill steps.


Surrogate Applications

When using non-pathogenic surrogate bacteria, three parameters should be considered. These are often referred to as the 3 “P”. These three parameters are critical for they can dramatically impact microbial inactivation.


Salmonella, Listeria, Cronobacter, Escherichia coli, etc.



Thermal processes: extrusion, dryers, ovens, roasters, etc.
Non-thermal processes: HPP, UV, chemicals, etc.
Cleaning & sanitation protocols



Low water activity products: nuts, seeds, herbs, spices, pet food, feed, cocoa, flour, grains, protein powders, snacks, etc.
Meat & Poultry, Fish, Beverages, Dressings & Sauces, etc.


The compatibility of Novolyze’s Surrogates has been verified for a wide range of applications, taking into account these three parameters.


Novolyze’s Surrogates, the First Range of Freeze-Dried, Ready-To-Use Surrogate Preparations

Novolyze developed the first range of freeze-dried and ready-to-use surrogate preparations.

Due to its capacity to significantly streamline and decrease uncertainty during validation studies, Novolyze Dry surrogate Technology received several recognitions, including the 2017 Food Safety Innovation Award delivered by the International Association for Food Protection (IAFP) and the 2018 Food Expo Innovation Award delivered by the Institute of Food Technologists (IFT).


Advantages of Novolyze Dry Surrogate Technology
  • Ready-to-use, no further enrichment step required before inoculation
  • Minimal impact of the inoculation on the intrinsic properties of dry ingredients
  • Compatible with a large portfolio of applicatios, robust scientific evidence of death time correlations
  • Easy inoculation at high levels (up to 8-log) from a few grams to several tons of food
  • Strong stability, long shelf life, easy storage & transportation
  • Standardized manufacturing process. Maximum reproducibility, maximum quality


At Novolyze, we are at the forefront of process validation. Our cross-functional team of validation experts, mainly composed of food microbiologists and process engineers, is able to assist you at all the stages of a validation project. Contact us for more information.

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