FERMENT – More than lactate in fermented dairy

Fermentation is a central technology for preserving fresh dairy products. Traditionally, the preservative effect has mainly been attributed to lactic acid produced by starter cultures, as it lowers pH and thereby inhibits the growth of spoilage microorganisms and pathogens. Despite this, a considerable proportion of fermented dairy products is still wasted each year due to limited shelf life.

By: Anne Lau Heckmann

Recent research indicates that lactic acid itself has limited antimicrobial activity beyond its acidifying effect. At the same time, other short‑chain carboxylic acids (SCCA) with stronger antimicrobial potential have been identified in fermented dairy products, though typically at low concentrations. This suggests that the role of fermentation in natural biopreservation is more complex than previously assumed.

The objective of FERMENT is to improve the understanding of natural preservation mechanisms in fermented dairy products by studying the diversity, formation and antimicrobial effects of SCCA beyond lactic acid. The project investigates whether these compounds contribute significantly to food safety and whether fermentation processes can be further optimised to extend shelf life. The project combines analytical methods, microbiological testing and fermentation studies. The project will first map SCCA profiles in a range of fresh fermented dairy products. The antimicrobial activity of individual acids and selected combinations will then be assessed against relevant spoilage organisms and foodborne pathogens in model systems and dairy matrices. In addition, the project will study how starter culture metabolism influences SCCA formation using genomic analyses, metabolic modelling and controlled fermentations, including storage studies.

The project is expected to provide new knowledge on how fermentation metabolites contribute to microbial stability in dairy products. This knowledge can form the basis for targeted selection of starter cultures and optimisation of fermentation conditions, supporting natural preservation strategies, reduced food waste and improved sustainability in the dairy sector.