Effectiveness of new molecules against widespread moulds for food-safe hardwood and softwood packaging

Abstract

Wood packaging materials (WPMs) are widely used for collecting, storing and trading a wide range of products, including fresh fruit, vegetables and grains. The occurrence of moulds on WPMs used in the food industry must be avoided at every stage of the supply chain. This study aimed at (1) characterising fungal mould populations developing on fresh boards of hardwoods (European beech and poplar) and softwoods (Norway spruce and eastern white pine) commonly used by the packaging industry, and (2) assessing the effectiveness of two new molecules approved to come in contact with food, potassium sorbate and copper-8-quinolinolate, against mould growth and sporulation. A total of 322 fungal isolates belonging to 182 putatively different morphotypes were obtained. Spruce and beech boards were found to harbour a higher number of putatively different morphotypes compared to poplar and pine. The spectrum of fungi mostly included Ascomycota and the most abundant taxa were Trichoderma spp. and Penicillium spp. The effectiveness of the two new molecules (potassium sorbate approved for the use in both Europe and USA, and copper-8-quinolinolate approved for the use in USA only) was assessed on treated test pieces by inoculating conidial suspensions combining the three most common fungal species for each wooden material. Both preservatives showed comparable effectiveness and significantly reduced (P < 0.05) mould mycelial growth and sporulation on all the tested wooden materials compared to untreated controls, representing a suitable option for the control of moulds on WPMs.