Fermented dairy

We develop and test the performance of microbes in prototype cultured products.

Fermented dairy products

Microbial fermentation is an integral part of transforming milk to a range of dairy products such as cheeses and yoghurts. Different bacteria are used to achieve unique flavour, taste and texture properties associated with different types of cheeses and yoghurts.

Fermented food products can also enhance nutrition and deliver probiotics.

Lab-scale evaluation

Small quantities of fermented dairy products are prepared to assess the performance of microbes to optimise fermentation (e.g. pH kinetics and temperature) and to profile metabolites, tastants or viscosity(external link)

Applications include screening commercially interesting microbes, including evolved bacteria(external link), indigenous microbes(external link) or commercial strain combinations.

The graph on the computer monitor to the left shows in situ rheological measurement to determine quality attributes of microbes during fermentation (10-20 mL volume).

The graph on the computer monitor shows in situ rheological measurement to determine quality attributes of microbes during fermentation (10-20 mL volume).

Differences in the physicochemical properties of drinkable yoghurts from New Zealand and China

The published paper can be accessed through this link:

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High throughput micro-rheology

A laser-based micro-rheology instrument has been developed for non-invasive screening of evolved bacteria for exopolysaccharides (EPS) production. This new capability enables us to rapidly screen for changes in texture, avoiding lengthy traditional rheology testing procedures.

Rapid screening consists of loading samples into a standard well plate and placing the plate inside the instrument as shown in the image. A Microsoft Windows application defines the plate size, contents and various experimental parameters. Full 3D (x-y-z) motion delivers each sample to the laser's measurement location. Capturing data from a 96 well plate takes 3-4 minutes, and the entire plate is re-measured every 10-15 minutes over several hours. Temperature is controlled using a simple enclosure.

Food grade pilot scale processing for product manufacture

Inside our food grade pilot processing facility in Te Ohu Rangahau Kai, Palmerston North.

We develop fermentation processes to mimic commercial conditions and produce food-grade prototype cheese and yoghurt products in our state-of-art food-grade pilot processing facility under an MPI-audited risk management programme (RMP). The products can be used for sensory profiling and consumer evaluation studies(external link) as well as shelf life storage evaluation.