By) 
THe Errect or PRESERVATIVES ON THE DEVELOPMENT OF 
PENICILLIUM. 
By KaTuHerINne Gotpen Birrina. 
In examining ketchup fer the organisms present, it was noted that the 
hype of moulds in preserved ketchup were swollen and distorted. In 
many of the brands of ketchup, the mould present was the common blue 
mould, Penicillium. As this mould is apparently omnivorous in habit, 
thriving and fruiting on many media, has been used in many physiological 
investigations to determine the nutritive value of many compounds, grows 
normally in liquid media, and fruits normally in a saturated atmosphere, 
is regular in its germinative power, and, so far as known, constant in 
form, it was selected to determine the effect of sodium benzoate, used in 
varying quantities, on its structure and development. ‘The media used in 
the experiments were tomato bouillon, tomato gelatin, and tomato pulp, 
and were selected because the tomato juice and pulp are present in ketchup, 
and also because they do not alter the toxic properties of the agents used 
toward the fungus. Afterwards the condiments used in ketchup weve 
tested and also the ordinary food preservatives, though not so extensively 
as the sodium benzoate. In these latter experiments tomato bouillon was 
the oniy medium used. 
The bouillon was made by adding to a can of tomatoes an equal vol- 
ume of water, boiling for about half an hour, and then filtering. The 
filtrate is clear, and a good medium for growth. It has an acidity of ap- 
proximately .2% calculated as citric acid. Fer the tomato gelatin, 10% of 
gelatn was added to the tomato bouillon, cleared with egg, and filtered. 
The tomato pulp was obtained from a factory, and was made fram whole 
tomatoes. To these media the sodium benzoate was added in the various 
amounts used in factory practice. Before sterilizing the media, calen- 
dered paper was tied closely over the cotton plug to prevent the distilla- 
tion of the benzoate. After sterilization and cooling, the media were 
inoculated with spores from a vigorously growing culture of the mould. 
During development, the cultures were kept at room temperature, unless 
otherwise stated. The method of culture was by moist chambers and flasks 
for the bouillon and gelatin, and Petri dishes for the pulp. The moist 
