Fungi present in some recycled fibre pulps and paperboards

The occurrence of fungal species in 37 samples, including wet recycled fibr e pulps, recycled fibre paperboards, recycled fibre kitchen rolls, virgin f ibre dry pulps and process water, was investigated. A total of 230 isolates (13 yeasts and 217 moulds) were identified. The fungal biodiversity of pul ps and process water was rich in terms of overall variety of genera (yeasts 5, moulds 31) and species (yeasts 8, moulds 69). The predominant genera we re Penicillium (21% from the isolates), Trichoderma (20%), Aspergillus (14% ), Mucor (10%), Paecilomyces (7%) and Geotrichum (3%). Yeasts were rare in the samples. The genera isolated were Candida (46%), Cryptococcus (23%) and Rhodotorula (15%). The drying stages of the paper and boardmaking processes eliminated very ef fectively all the fungi present in the recycled fibre pulps and process wat er. Only Gilmaniella humicola occurred frequently in the paperboard samples , probably as a secondary contaminant from the mill environment or from the boardmaking chemicals used. Although some potential food spoilage species and opportunistic human pathogens occurred in the recycled fibre pulp sampl es, they were not detected in the recycled fibre paperboards. The kitchen r oll samples and five of six virgin fibre pulp samples were free of fungi.