Viscosity measurement in a production setting is typically used to decide if a product is within quality specification limits.
Measuring product density, chemical composition or production flow rates alone does not provide information about the viscosity of the product.
Since many food products are complex multiphase mixtures containing particles, and generally behave as non-Newtonian liquids during flow, the in-process viscosity may be difficult to measure
and to relate to off-line measurement. 
In reaching the decision to accept or reject a food product based on its viscosity, it is important to compare measurements made at the same temperature, and at the same shear rate, as well as
to consider whether factors such as sampling procedures are influencing viscosity measurement.

Fonte: www.foodsciencecentral.com