Lactobacillics plantarum was for some time considered to be the principal species responsible for the acid fermentation of cucumbers. Etchells and Joiies (7) isolated and studied 49 cultures from commercial fermentations brined a t 20, 30 and 40" salometer (5.3, 7.8 and 10.6% NaC1). All 49 cultures were found to be L. plantarum. Of 20 cultures isolated from commercial fermentations by Costillow and Fabian ( 4 ) ) 16 were found to be L. plantarzcna.Recent studies (12, j 3 ) of a large number of cultures isolated from fermentations brined in glass jars under laboratory conditions have indicated that there may be up to 5 species of lactic acid bacteria active in cucumber brines. The species found were Leuconostoc meselzteroides, Xtreptococczcs f aecalis, Pediococcus cerevisiae, Lactobacillus brevis and L. plawtaritrn in the order of increasing prevalence. These workers reported that the flora may be influenced by both salt-concentration and temperature of fermentation. Rorg et al. ( 1 ) identified 92 cultures of acid-forming bacteria from commercial cucumber fermentation; " 51 were similar to Pediococcus cerevisiae, 28 resembled L. plantarum and 13 belonged to another species of Lactobacillus."This study was initiated to determine the types of acid-forming bacteria active in cucumber fermentations in Michigan. Also, we wished to investigate what effects, if any, that sorbic acid might have on the prevailing types present. METHODS Fermentations Studied and Methods of SamplingEight hundred and f orty-eight cultures of acid-forming bacteria mere isolated from 84 cucumber fermentations during the brining seasons of 1953 and 1954. The source of the cultures isolated as to salting stations, fermentations, brining treatments and samples are given in Table 1. The 12 fermentations studied in 1953 were all brined in 45-gal. barrels at one salting station. I n 1954, 53 lots were brined in barrels located at 5 salting stations and the other 19 fermentations sampled were commercial lots located at the same 5 stations.I n 1954, one-third of the barrels of each brining treatment a t each station were treated with 0.1% sorbic acid, one-third with 0.05% sorbic acid and the other one-third

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