In order to tailor inventory control to urgent needs of grocery retail, the discrete-event simulation model with realistic perishability mechanics is proposed in the paper. The model is stochastic and operates with multiple products under constrained total inventory capacity. Besides, the model under consideration is distinguished by quantity discount, uncertain replenishment lags and lost sales. The paper presents both mathematical description and algorithmic implementation. An optimisation framework based on a genetic algorithm is also proposed for deriving an optimal control policy. The proposed approach contributes to the field of industrial engineering by providing a simple and flexible way to compute nearly-optimal inventory control parameters.