Perfect Day is developing animal free dairy proteins using microbial engineering and cellular fermentation technologies. In 2019, Perfect Day successfully produced cell based whey protein that was incorporated into a small run of 1000 units of ice cream.

Perfect Day is producing β-Lactoglobulin, the primary protein that makes up bovine whey. The β-Lactoglobulin is produced by Trichoderma reesei for use as a source of protein in food at levels up to 35%. β-Lactoglobulin as described by Perfect Day is a white to cream colored powder containing β-Lactoglobulin that is produced through fermentation of the Trichoderma reesei fungus strain that has been specifically engineered by Perfect Day to optimize production of β-Lactoglobulin. This production strain of fungus is fermented under controlled conditions through which the β-Lactoglobulin is subsequently secreted into the fermentation media. The secreted biomass undergoes a centrifugation process to separate the desired biomass (β-Lactoglobulin) from the fermentation media and further concentration and filtration processing enables the protein to be integrated into a variety of products including yogurt, ice cream, and cheese.