happen to suffer from an allergy to the spores of moulds or act-
inomycetes, but, although they cannot grow in it, the atmosphere forms
an important vehicle for the spread of many micro-organisms, and the
subsequent contamination of foods.
2.3 Micro-organisms of Soil
The soil environment is extremely complex and different soils have their
own diverse flora of bacteria, fungi, protozoa and algae. The soil is such
a rich reservoir of micro-organisms (Figure 2.8) that it has provided
many of the strains used for the industrial production of antibiotics,
enzymes, amino acids, vitamins and other products used in both the
Figure 2.6 Cladosporium cladosporioides
Chapter 2 11