Clean Label Antimicrobials: How to Find Them?

Originally Published: October 16, 2015
Last Updated: October 16, 2015
Microbial fermentation is instrumental in food preservation, and in the future, will be used to produce new clean label foods

Schuren-photo-to-post-on-blogOctober 16, 2015–Global Food Forums, Inc. — The following is an excerpt from the “2015 Clean Label Report,” sponsored by Loders Croklaan, RiceBran Technologies and SunOpta.

There is a market demand for fresh products with extended shelflife. TNO, the Netherlands-based company, has made a commitment to identify and isolate antimicrobial compounds from a variety of sources as part of their commitment to help find “clean
label” alternatives for the food processing industry, said Frank Schuren, Ph.D., Senior Scientist Microbiology, TNO Microbiology & Systems Biology.

It is well-known that many herbs and spices have antimicrobial activity. However, research on these properties is lacking, and, where it has been done, the research tends to focus on food pathogens—not spoilage organisms, such as yeasts and molds.

TNO has conducted screening studies that have not only looked at the antimicrobial properties of a wide range of spices, but looked at variables essential to their functionality in food systems, such as the effects of pH and concentration. Schuren noted that
antimicrobial compounds that adversely affect desirable qualities, such as flavor, aroma or color, simply would not be accepted in the marketplace.

The challenge is not only to determine which spices and herbs have antimicrobial properties, but to look at how they perform in food systems alone or in combination with other products. The objective is to find synergies and interactions of compounds that
will provide significant inhibitory effects, while having less impact on a food’s sensory quality.

This has spurred the investigation of novel approaches to locate effective, usable antimicrobials from nature. One tool adopted by TNO is the use of bacterial cells as a biosensor and, thus, as a predictive tool. The company has established that gene expression in cells correlates with external stress factors, like temperature and
pH. It has used this to better understand cell behavior in food processing environments.

The research process employed first identifies model spoilage strains, then sequences a strain’s genome. Analytical tools, such as microarrays and next-generation sequencing, are then used to assess specific stress responses. This helps to identify biomarkers
that can be used in screening approaches to look for ingredients with desired effects. For example, model spoilage strains may then be exposed to different herbs and spices, or their extracts, to clearly identify microbial activity incorporating variables such as acidity and concentration.

One application is to look at different spoilage organisms in the food processing environment and evaluate how these might be controlled. Utilizing environmental sampling techniques, such as air sampling, and subjecting these samples to taxonomic profiling of the microbial communities, TNO has identified the different organisms found in such environments, Schuren reported. By sequencing isolates, they have the capability of identifying bacterial flora, fungi, eukaryotes and other organisms.

Up to 20 million sequences and more than 400 samples may be evaluated in a single run. Understanding the microbial flora in an environment allows the implementation of targeted solutions that are sustainable. It also provides users with the ability to reduce dependence on chemicals traditionally used for cleaning and sanitizing.

Another function is to expand the application of microbial fermentations. Fermentation has been an integral part of food preservation for thousands of years and is responsible for commercial products, such as wine, beer, cheese, bread and many others. The goal is to take these processes further and utilize fermentation technologies to produce more foods that taste good but can be marketed with a clean label.

Frank Schuren, Ph.D., Senior Scientist Microbiology, TNO Microbiology & Systems Biology,