Penicillium and Aspergillus in the Food Microbiology Laboratory

Abstract

Species of these two genera have long been dominant among the spoilage flora of a range of foods, especially those with reduced water activity and low pH. As various lobbies seek to reduce levels of humectant preservatives and acids, such spoilage is likely to increase and, where controlled chill is used as a substitute, psychrotrophic Penicillia have a particular advantage. Although some species are ubiquitous, the presence of others can be strongly indicative of particular types of problem (e.g. EUTotium spp. and marginal moisture abuse). The concept of recognising Indicator and Index organisms is not unknown in Bacteriology, yet has been slow to be adopted in Food Mycology, mainly because of the difficulty in identification. Mycology is advancing rapidly, with clarifications of taxonomy, simplification of keying and new analytical procedures (e.g. E.L.I.S.A. and lectin binding). It is now time to consolidate those achievements so that recognition of important species, especially in Penicillium and Aspergillus, and assessment of their significance, are made available to laboratories that lack the services of an expert mycologist.