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Effect of different levels of propionic acid on the growth of Micropolyspora faeni (A.94) and Thermoactinomyces vulgaris (A.64)
Author(s) -
Pizarro Esteban A.,
Davies Mervyn H.,
Warboys Ivan B.
Publication year - 1973
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740241106
Subject(s) - agar , food science , biology , filter paper , chemistry , chromatography , bacteria , genetics
The effects of propionic acid incorporated in agar and on filter paper discs on the growth of Micropolyspora faeni (A.94) and Thermoactinomyces vulgaris (A.64) showed different results between the two methods of testing, with agar showing total inhibition of both micro‐organisms even at the lowest level of acid (0.1%). The extent of diffusion of propionic acid from filter paper discs was significant up to 2.5% acid level beyond which there was no significant effect on pH changes in the surrounding medium. Both organisms varied in their degree of sensitivity to propionic acid and to pH. Both organisms grew at a pH of 6.5 and at all acid levels between 0.01 and 0.5%.