The efficacy of potassium sorbate-coated packaging to control postharvest gray mold in raspberries, blackberries and blueberries

• The efficacy of potassium sorbate-based packaging is assessed in vivo.
• Shelf life of packed berries were extended by delaying the growth of Botrytis.
• The packaging worked better for raspberries than blackberries and blueberries.
• Packaging transparency and the flavour of the fruits remained unaltered.

The aim of this work is to build on the success of in vitro studies of an active packaging, produced by coating the surface of post-consumer recycled polyethylene terephthalate (PCRPET) package with an aqueous silicone solution (2%, v/v) containing an antifungal agent (potassium sorbate, KS). Antifungal efficacy was evaluated, in vivo, during the storage of raspberries, blackberries and blueberries by examining their shelf life extension. The packaging effectively delayed the growth of Botrytis by extending its lag-phase, which, in turn, extended the shelf life of the berries by up to 3 d. Among the three berries tested, the packaging proved to be more advantageous in the case of raspberries, due to their physiological characteristics and shorter shelf life. Based on sensory panel evaluations, it was shown that the coating, containing KS, did not influence the packaging appearance and transparency, and the fruit did not suffer from any off-flavor development.