Intense light pulse treatment as alternative method for mould spores destruction on paper–polyethylene packaging material Original Research Article

Intense light pulse (ILP) is one of the emerging non-thermal techniques investigated as an alternative to traditional thermal treatment because it has been proven to be effective for microbial inactivation on food surfaces and food packages. The aim of this study was to evaluate the possibility of using pulsed light treatment for the effective killing of moulds on paper–polyethylene packaging material. Coupons of 20 × 20 mm paper–polyethylene were artificially contaminated with Cladosporium herbarum, Aspergillus niger, Aspergillus repens and Aspergillus cinnamomeus than subjected to different light energetic densities (from 0.244 to 0.977 J/cm2) for different durations (from 10 × 10−3 to 30 × 10−3 s). The results showed that there is a significant reduction of population along with an increase of light fluence and ILP treatment duration. The highest level of inactivation achieved in this study was about a 2.7-log reduction, which is more than enough for a normal contaminated packaging material. It is estimated that pulse light treatment could lead to an effective reduction of moulds, being also possible to obtain a sterile surface of the packaging material. Blastospores as those produced by C. herbarum are easier destroyed (z = 0.795 J/cm2) than fialospores as those produced by aspergilli (z = 0.81–0.927 J/cm2). Spore colour seems to play some role in spore resistance to light pulses: green fialospores, as those produced by A. repens, has higher z values (0.927 J/cm2) than the black or brown ones as those produced by A. niger (z = 0.81 J/cm2), and A. cinnamomeus (z = 0.875 J/cm2) respectively.