SYSPOR – Control of acid resistant sporeformers in acidic dairy products at ambient storage

SYSPOR focuses on acidified dairy foods, i.e. yoghurts, yoghurt drinks, smoothies, stored at ambient temperatures for exports in countries with temperate or tropical climates. Currently specific guidelines lack for heat treatment of ambient acid foods (pH ≤4.6). This is unlike for ambient low acid foods (pH>4.6), where clear heat treatment targets exist for both pathogens and spoilage microorganisms. The lack of specific guidelines means that different heat treatments are used, which may not offer a high level of protection against spoilage micro-organisms or are overly strict and result in inferior products from a quality point for view.

By: Grith Mortensen

The objective of the current project is to understand how to optimally heat treat and formulate ambient acid dairy products to control acid resistant sporefomers and ensure safe and high quality products. This is done by identifying key species of acid resistant sporeformers, determine the D-values, propose a target heat treatment, evaluate hurdle effects (organic acids and heat treatments) on growth of sporeformers, and finally validate the effectiveness hereof.

Projectperiod: January 2021 - December 2023

Budget: 3.509.750 DKK

Financing: Milk Levy Fund, Arla Foods

Project manager: Marianne Hammershøj

Institution: Department of Food Science, Aarhus University 

Participants: Arla Foods