Sensory Detection
Chemical concentration limits define the point at which human senses can detect the presence of a specific volatile compound. In food contact packaging, the organoleptic threshold determines the maximum permissible migration of volatile organic compounds from the ink or adhesive layers. Even when a migrant is non-toxic, exceeding this concentration can alter the flavour or aroma of the packaged food, leading to customer rejection.
The threshold varies widely between compounds, with some chemical families detected at parts per billion. This sensory limit is much lower than the safety limit for many common solvents. Because of this high sensitivity, the testing methods must isolate the packaging material from any external ambient odours that could interfere with the evaluation.
Odour Evaluation
Standardized sniff tests assess the sensory neutrality of printed paperboards. To measure the organoleptic threshold of a specific printing run, laboratories conduct sensory trials where a panel of trained assessors evaluates board samples sealed in glass jars. The board is kept at elevated temperatures to accelerate the release of volatile substances.
If the panel detects any off-gassing, the batch is deemed unsuitable for direct food contact.
Packaging Safety
Barrier layer selection prevents the migration of unwanted compounds into dry food. When using recycled board, an organoleptic threshold study guides the selection of functional barrier coatings or polymer liners. These barriers must block the transmission of mineral oils and residual solvents from the recycled pulp.
Ensuring that the migration remains below the detection limit protects both the product quality and the brand’s reputation.
