Off-flavour release from packaging materials and its prevention: a foods company's approach

Off-flavours in packed food are causes for consumer complaints. Often, they are related to packaging materials. For food companies, this represents not only costs related to production, but also a possible loss of brand confidence and market share. The origin of packaging-related off-odours are many sided. Odours derive from the degradation of base packaging materials and their converting processes, including printing, coating and lamination as well as the interaction between food and packaging. Many substances and groups of substances have been identified so far. In spite of the fact that the quality of packaging materials is clearly defined in the specifications (e.g. limit for residual solvents, standardized odour and taste transfer tests), off-flavour cases still do occur. This paper sets out ways of avoiding such problems, even in factories and laboratories which are not so well equipped. Prevention at Nestlé is based on several pillars. For a number of years, a sensory panel at the central laboratory has been specialized in and trained on packaging off-favours. The panel can describe and identify odours and their origin. To confirm the results by instrumental analysis, various extraction and separation techniques are available, including distillation/extraction techniques and direct thermal desorption followed by gas chromatography coupled with mass spectroscopy and an olfactory sniffing port. However, this knowledge must also be present in the operational plants where the problem usually originates. To manage this knowledge transfer, two tools were introduced to build up sensory panels that can evaluate packaging material. First, an aroma library kit was developed that contained odours that are often involved in off-odour cases. For each odour, a typical descriptor and the chemical composition are given. Beside that, information is added about the occurrence. Second, a glossary, which contains descriptors for packaging-related off-odours, was published. This small booklet helps to unify the odour descriptions, especially thanks to its translation into three important languages. This paper describes the tools mentioned above, as well as examples and limitations for their application.