This paper proposes a multi-objective optimization model that provides an effective method for minimizing traceability effort by minimizing the food safety risk caused by lot aggregation at a grain elevator. A mathematical multi-objective mixed-integer programming (MIP) model is proposed with two objective functions that allow in calculating the minimum levels of lot aggregation and minimum total cost of blending grain. Constraints on the system include customer contract specifications, availability of grain at the elevators and the blending requirements. The solutions include quantities of grain from different storage bins to be used for blending for a shipment while using the minimum number of storage bins and minimum total cost. The numerical results are presented for a corn shipment scenario to demonstrate the application of this model. Pareto optimal front is computed for the problem for simultaneous optimization of lot aggregation and cost of blending. Sensitivity analysis is conducted to analyze the application of the model under different operating conditions. (C) 2010 Elsevier Ltd. All rights reserved.