Temperature and water activity minima for growth of spoilage moulds from meat.

Abstract

Five species of fungi were isolated from mould spoilage on meat other than black spot. 'White spot' colonies yielded Chrysosporium pannorum or an Acremonium sp.; 'whiskers' colonies yielded Thamnidium elegans or Mucor racemosus, and blue-green colonies yielded Penicillium corylophilum . Chrysosporium pannorum was moderately xerotolerant with a minimum growth temperature of -5 degrees C. The Acremonium sp. and P. corylophilum showed a similar level of xerotolerance but had a minimum growth temperature of -2 degrees C. Mucor racemosus was no more xerotolerant than many spoilage bacteria and did not grow below -1 degree C, but grew rapidly at 3 degrees C and above. Thamnidium elegans grew at -7 degrees C on supercooled medium and an intrinsic minimum growth temperature of -10 degrees C was indicated. However, the low xerotolerance of this species precluded growth on frozen media below -5 degrees C. It seems therefore that -5 degrees C is the practical limiting temperature for mould growth on meat, and mould spoilage usually indicates that surfaces of freezer stored meats have approached and possibly exceeded 0 degrees C.