The effects of pH values and NaCl concentrations on the growth rates of five species of lactic acid bacteria commonly associated with the sauerkraut fermentation were determined in filter-sterilized cabbage juice. Growth rates of all cultures, with the exception of Pediococcus cerevisiae, were retarded by addition of salt, lower pH, or interaction of both pH and salt. Based upon lag and generation times, P. cerevisiae was the culture most tolerant to the pH and salt concentration employed, whereas Streptococcus faecalis was the most sensitive species. Of the heterofermentative cultures, Lactobacillus brevis was less subject to growth inhibition than Leuconostoc mesenteroides.
Under conditions simulating those found during the initial phases of the sauerkraut fermentation (2.25% salt, pH 6.2), L. mesenteroides displayed the shortest lag and generation times of all cultures examined. This rapid growth rate coupled with a marked accelerated death rate may explain, in part, the reason this species is both the first to dominate and the first to die during the early phases of the sauerkraut fermentation. Although cabbage juice previously fermented by L. mesenteroides appears to inhibit growth of P. cerevisiae, it had no apparent inhibitory or stimulatory effects on the other cultures.
Commercially processed sauerkraut, packaged in plastic bags, was evaluated for product stability following storage at 2, 20, 32 C. When stored at 2 C in the presence of benzoic acid and potassium metabisulfite, the product was stable for more than 8 months, whereas at 20 and 32 C the shelf life was reduced to 20 and 13 weeks, respectively. The reductions in shelf life were due to development of excessive discoloration (browning) and objectionable flavor formation. These defects appear to be caused by chemical rather than microbiological actions. In addition to serving as effective anti-microbial agents, the chemical preservatives (presumably sulfur dioxide) showed protective effects in retarding losses of naturally-occurring ascorbic acid found in sauerkraut. Under similar temperatures of storage, fresh sauerkraut containing no chemical additives had shelf life values of 22, 1.5, and 0.75 weeks, respectively. When stored at 32 and 20 C, the major defects (swollen or broken bags) were attributed to the actions of yeasts. Storage at 2 C markedly arrested and reduced viable yeasts counts, thereby extending the shelf life of the bagged product.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.