[About the identification of sources and routes of mould contamination of bread in large bakeries (author's transl)].

Abstract

In order to identify sources and routes of the contamination of bread by moulds, the microbial germ content of the air and machine surfaces was investigated in 25 large bakeries of different geographical position and size. On its way from the baking oven to the delivery station, the bread passes through production areas likely to be loaded with more than 90,000 mould spores/cbm air. With a germ content of the air in the bread storage rooms from 85 to 5,000 mould spores per cbm, bread contamination by 10 to 400 mould spores per 100 sq.cm must be expected to take place in the course of one hour. The germ content of the air in bread factories depends, among other factors, on the dust content of the air, the producton processes, the time and type of cleaning as well as on the fresh-air supply system for the production and storage areas. Especially in the bread slicing and packaging areas, a number of production-related sources of microbial spread exist which should be eliminated. The "knife oils" used for the slicing tools are occasionally found to be heavily contaminated with mould and yeast already at their arrival at the bakery. The continuous use of these oils leads to a considerable enrichment with microbial germs.