Analysing food bacteria strains at genomic level helps limit food spoilage, says NIZO

Analysing food bacteria strains at the genomic level can help limit food spoilage by determining whether a lactic acid bacterium is a food spoiler, according to a study carried out by NIZO food research.

Commissioned by and in collaboration with Unilever R&D, the study tested 121 lactobacillus strains of six different species for their phenotypes relating to growth in carbon source and preservation environments.

The growth of these strains was measured on 21 carbon sources and under 27 preservation-related phenotypic parameters.

By relating the genome of lactobacilli species and strains with phenotypic parameters, NIZO scientists determined the genes responsible for growth in specific carbon sources and under specific conditions.

The match between the genotype and the phenotype was established using bioinformatics tools developed at NIZO.

NIZO Safe & Certain Research Team group leader Michiel Wels said the team found that differences between strains within one species are often larger than between species.

"Diversity at the genetic level determines whether a microbe will spoil a food under specific conditions."

Wels added, "Further development to reduce the time from cell extraction to genotypic characterisation will enable routine analysis to be carried out in production plants in future.

"With the current bioinformatics tools and databases available at NIZO, we are well prepared to fill this market need."

Lactobacilli are spoilage bacteria found in sauces, soups, condiments and spreads, where contamination is likely to occur on repetitive use.

By knowing the conditions under which the species and their strains grow, risks can be assessed and product specifications can be identified to minimise the growth of common spoilage bacteria.

Improved characterisation of potential contaminants helps define the limits for preservation of particular food varieties, according to NIZO.