Turning up the heat: evaluating thermal treatments for phage management in dairy plants

Executive Insight

Bacterioiophage disruption remains one of the most persistent risks to industrial dairy fermentations. This research highlights why dairy producers need customer orientated strategies in managing the phage risk, particularly when using heat treatments.

By consolidating decades of research this study shows that heat treatment alone is not a reliable phage-control strategy in dairy processing. Phage survival depends on the specific isolate, the dairy matrix, and how heat is delivered.

Dairy plants should therefore replace universal “kill steps” with validated, product-specific multi-hurdle control strategies.

Why This Research Matters

Bacteriophages can infect starter cultures and cause delayed or failed fermentations. This can result in production disruption, downgraded products, reduced yields, and major financial losses. The research challenges the fact that current heat treatment protocols reliably control this risk. It also shows that repeated sublethal heating may select for increasingly heat-resistant phage populations.

About the Authors

IFF contributors Dr. Damian Magill, Sr. Scientist II, R&D – H&B, and Gwendoline Parigi, Research Associate, IFF Health & Biosciences, contributed to this research.

Together with an interdisciplinary team of academic and IFF researchers conducted the study. Their expertise spans microbial genetics, phage-host interactions, and industrial fermentation systems.

Practical Applications in Food Biosciences

The findings provide a consolidated basis for optimizing heat treatment protocols for phage management in the dairy industry. The study highlights that performing tests within the actual product matrix and under experimentally consistent conditions is crucial for obtaining industrially relevant results regarding phage heat treatment protocols used by dairy product manufacturers. In addition, one should pay attention to complete inactivation and survivor kinetics rather than simple average log reduction when optimizing these protocols.

How This Research Was Conducted

The authors conducted a data-driven literature review, compiling more than 1,000 heat-inactivation observations from over 20 studies published between 1954 and 2022. The dataset included multiple phages, bacterial hosts, temperatures, exposure times, and suspension matrices. The team compared the results to identify thermal-resistance patterns, matrix effects, non-linear survival kinetics, and mechanisms of phage adaptation.

Explore the Full Scientific Paper

Read the full peer‑reviewed publication in Frontiers for detailed methods, data, and results.