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

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

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. 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.

The project's results will contribute to the dairies being able to deliver safe and durable products of higher physical stability and sensory quality in the future. Additionally, documenting food safety and understanding how technology and food safety interact can eventually pave the way for the export of fermented dairy products to temperate and tropical climates, where the products are transported and stored outside the cold chain.

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


Publications and presentations

Initial article published in Mælkeritidende:

Mælkeritidende 2022 no. 11


The results originating from the project will be published on this page when they become publicly available.

Grith Mælk 1

Grith Mortensen

Chefkonsulent, Branchesekretariat mejeri, Landbrug & Fødevarer/Skejby

Mobil: 40964114