Profile of Penicillium species in the pear supply chain

Postharvest fruit decay caused by Penicillium pathogens is considered to be one of the most important challenges in the pear industry resulting in market-end losses. Moving export fruit through different environments exposes the product to extensive handling, temperature variations and microbes. Therefore, the profile of Penicillium spp. present in the pear export chain from South Africa (SA) to the UK was studied over a four-year period. Sampling was done at two packhouse facilities, controlled atmosphere and cold storage areas in SA and at two repack facilities and cold storages as well as a distribution centre and a retailer in the UK. Sampling consisted of swabbing walls and floors and using active and passive air sampling. In total, 5056 isolates were obtained, purified and grouped into 282 morphological groups. Of these, 350 representative isolates were selected for further identification. The five most dominant species in the pear chain were: P.glabrum (2340%), P.chrysogenum (1513%), P.crustosum (1416%), P.brevicompactum (896%) and P.expansum (839%), of which the latter three were confirmed pathogenic on pears. This study provides a framework to monitor the inoculum potential in environments that fruit move through while being exported.