Many food processing operations involve the flow of solid-liquid mixtures, often with simultaneous heat transfer. Prediction of the effects of processing requires understanding of the heat transfer and flow properties of the two phases. The fluid mechanics literature contains much information on the radial migration of particles in vertical how, but it is not certain how this might apply to food processing. A series of experiments has been carried out to study the behaviour of single food simulant particles (5-10 mm) in carboxymethyl cellulose (CMC) solutions, in 44 mm vertical pipes, to study whether migration occurs. Results confirm that migration can be significant in laminar flows of food fluids : effects are greater for larger particles of high density flowing in low viscosity fluids.