Mould Growths upon Cold-store Meat. 139 
meat these growths are profuse and are practically indistin- 
guishable from species of Mucor. The genus Thammnidium differs 
from Mucor in the presence of two different kinds of sporangia, 
large and small, but in the natural occurrence of Thamnidium 
upon meat the small sporangia are either few or non-existent 
so that it appears like a Mucor. When grown under laboratory 
conditions, however, both types of sporangia are usually formed; 
upon nutrient agar small sporangia predominate, but upon 
cooked meat the reverse is the case. Upon fresh meat in the 
laboratory large sporangia sometimes occur to the exclusion of 
small ones. 
Two species of Thamnidium were frequently isolated from 
cold-store meat, 7. elegans and T. chaetocladioides, and of these 
the latter was the more common. It is of interest that these 
fungi are of rare occurrence upon other substrata, although 
upon mouldy meat they seem to be particularly common. 
At ordinary temperatures and up to 20° C. these species grow 
well; at 25°C. T. elegans grows fairly well but 7. chaetocladi- 
oides develops hardly at all, the spores becoming much swollen 
‘and forming curious amoeboid-looking cells. At 30° C. neither 
species develops. 
So far there has been only the slightest signs of growth of 
either of these species at — 6°C., but at a temperature of 
I-2° C. they grow profusely. They also grow at a temperature 
of — 1° to — 0:5° C.; development at temperatures between this 
and — 6° C. has not yet been tested. Bidault (2), however, states 
that T. chaetocladiowdes (= Chaetostylum Fresenit) grows at 
— 10° €. 
The spores and even young mycelia will retain their vitality 
for long periods at a temperature of — 6° C. Thus meat inocu- 
lated with spores of Thamnidium chaetocladioides in October 1919 
and placed in the cold store either immediately or after 24 hours, 
developed profuse growths of this fungus directly after removal 
to ordinary temperature in January 1921. 
Mould spores of this type, therefore, which may have been 
deposited on the meat before being placed in store, remain 
living for long periods at low temperatures, and if there is a 
breakdown of the refrigerating plant, causing a rise in tem- 
perature to about freezing point, it is to be expected that these 
lurking moulds will develop profusely. Where such “whisker” 
growths are apparent on the meat, it is probable that the meat 
has been exposed to a temperature of 0° C. or slightly above 
,for some time during storage. These moulds are entirely super- 
ficial and can readily be removed witha cloth. If unaccompanied 
by putrefactive bacteria, meat affected by these moulds is not 
dangerous for human consumption. 
