The structure of milk fat globules – the microscopic fractions that carry lipids such as fats in milk – have long been linked with milk’s emulsification properties, eg. how well it’s processed into butter and cream. But little has been known how the tiny globules interact with naturally-occurring bacteria.
New findings out of the Hebrew University of Jerusalem have now shed light on how differently-sized globules (MFGs) interact with pathogenic and probiotic bacteria in raw milk – paving the way for improved understanding on bacterial modulation in dairy.
The findings may also have important healthy and safety implications for food manufacturing in terms of informing ways to hinder the growth of pathogens or naturally improve the growth of good bacteria.
The research, led by professor Nurit Argov-Argaman from the Robert H. Smith Faculty of Agriculture, Food and Environment at the Hebrew University of Jerusalem, found that small milk fat globules promoted the growth of B.subtilis, a type of probiotic bacteria, in raw milk.
At the same time, the study found that E coli and staph aures were not affected by the size of MFG – but that the secretion of small MFGs protected against infection by E coli adherence.
All this was highlighted the importance of the native structure of the globules and showed that the chemical composition of milk fat doesn’t on its own provide the same bioactivity as the native structure of MFGs.
The researchers also concluded that the ability to change MFG size may play a role as a protection mechanism against pathogenic bacteria.
What is a milk fat globule?
A milk fat globule consists of a triglyceride core comprising several types of fatty acids, covered with three layers of phospholipids, proteins and glycoconjugates that together form a membrane. The membrane itself – known as MFGM – is highly sought-after in the nutrition and pharmaceutical industries thanks to a raft of health benefits.
Source:
The role of structure in the interaction between bacteria, mammary epithelial cells and milk fat globules from raw or “cultured” milk
Authors: C. Raz, N. Tzirkel-Hancock, M. Shemesh, N. Argov-Argaman
Published: Food Chemistry, Vol 467, 1 March 2025, 142244
DOI: 10.1016/j.foodchem.2024.142244