Single cell proteins (SCP) and oils (SCO) are promising alternatives for replacing conventional feed ingredients in animal and aquaculture fish feeds. The production costs of SCP and SCO need to be reduced by using inexpensive substrates (production by-products) suitable for cultivation of protein and oil producing microorganisms. This article reviews the availability of milk processing by-product – whey in Latvia, in 2019. Additionally, a simple production plant location optimization model is proposed, where no prior knowledge of location optimization or experience with dedicated software is required from the user. The case study demonstrated that the model is valid, and it can be used as a simple tool for resource acquisition from multiple sources to single production plant.