PRESERVATION BY SALTING 501 
between the bacteria acidity and score. Rahn, Brown and Smith 
(1909) found that salted butter kept better than unsalted. Micro- 
organisms were found in slated butter which multiplied slowly at —6° C. 
Thom and Shaw (1915) found that 2.5 to 3 per cent of salt was necessary 
to keep down mold growth in butter. 
Giltner and Baker (1915) in studying the effect of salt on the flora 
in butter have given some information which might be considered in 
this place. They found that 12 per cent of salt does not retard growth 
in all cases and that some bacteria are able to withstand 20 per cent of 
salt. Streptococci were found to be sensitive to salt while staphylo- 
coccl and micrococeci were not. The greater part of the yeasts and 
torule in butter cannot withstand as much salt as the cocci. Eight per 
cent of salt was believed to limit the physiological activities of most 
bacteria. Continued cultivation of some organisms on salt agar in- 
creased the salt tolerance. 
Weichel (1910) studied the effect of salt on the bacteria which are 
concerned in food poisoning. He found that by inoculating broth con- 
taining various amounts of salt with B. enteritidis, B. paratyphi “ B,”’ 
B. aertryke, that the cultures lived for between 33-95 days. Extending 
this study to meat inoculated before pickling, he found that inoculated 
meat showed a complete reduction in bacteria in 12 to 19 per cent of 
salt only after 75 days. Ptomaines formed by-bacteria were not de- 
stroyed by salting. In this connection Serkowski and Tomezak (1911) 
stated that 15 to 20 per cent of salt was required to be of prophylactic 
value with respect to bacteria which cause food poisoning. 
Lewandowsky (1904) observed a differential action of certain salts. 
A 25 per cent solution of sodium chloride was about as efficient as a 
30 per cent solution of potassium nitrate. The chlorides of potassium 
and sodium possessed about the same efficiency in solutions of equal 
molecular concentration. | 
Bitting (1909) in studying spoilage of tomato ketchup tried the effect 
of salts. Increasing amounts were put into 100 c.c. portions of bouillon 
which were later inoculated with molds and yeasts. A 5-gm. solution 
had no effect on molds. A 30-gm. solution allowed no development 
of the mold. The yeast did not develop in a 15-gm. solution. These 
data are interesting in connection with the work of Wehmer and Petters- 
son (1900). Wehmer isolated a yeast from herring brine which was 
inhibited by 15 per cent of salt. Pettersson confirmed this during a 
study of fish brine. 
Thom (1914) inoculated Czapek’s solution containing different 
amounts of salt with different cultures of penicillia. The results are 
