Spherical Lactic Acid-producing Bacteria of Southern-grown Raw and Processed Vegetables

Abstract

The frequency and levels of population of the spherical lactic acid-producing bacteria were determined on raw and processed yellow summer and zucchini squash, a variety of greens, green beans, okra, southern peas, and butter and lima beans, and on fresh cucumbers and corn flowers. Six taxa occurred consistently: Leuconostoc mesenteroides, yellow-pigmented streptococci, Streptococcus faecium, Aerococcus viridans, and S. faecalis and S. faecalis var. liquefaciens. The same taxa occurred with the same order of frequency on processed, frozen vegetables, but with a marked decrease in the occurrence of S. faecalis var. liquefaciens. S. lactis, S. cremoris, S. equinus, S. bovis, and pediococci were isolated infrequently. No other member of the viridans group of the streptococci and no member of the pyogenic group was isolated.Approximately 88 % of the cultures were identified. Total counts of the lactic-acidproducing bacteria rarely exceeded 105 per gram of sample, and there was a reduction by 90 % during the second year of study, probably because of drought. Only one bacterial species was found on 40% of the raw and 34% ofthe processed vegetable samples. Two or more species or taxa were present on the remainder of 153 raw and 56 processed vegetable samples. A. viridans was present on squash, greens, okra, and

Lactic acid bacteria associated with wine grapes from several Australian vineyards

“…The ethanol tolerance of these species requires more detailed investigation. Their association with the surface of plants and agricultural environments is well documented (Mundt et al 1967;Sandine et al 1972;Cai 1999;Chen et al 2005). Consequently, their isolation from the surfaces of grapes is not unexpected.…”

Microbial ecology of fermenting plant materials

“…Plants harbor a numerous and varied microflora. Although the numbers of lactic acid bacteria on plant materials are highly variable, most investigations have shown that their number is very low, often in the range of 10-1000 cells per g [12][13][14][15][16][17], which represents approx. 0.01-1.0% of the total microbial population.…”

“…On the living plant, the lactic acid bacteria are present on the outer surfaces where several species occur simultaneously [1,2,18]. Among the lactic acid bacteria found on plants ( Table 2), there appears to be a predominance of heterofermentative lactic acid bacteria, with Leuconostoc being the most frequently occurring genus [15,18]. The numbers of lactic acid bacteria on living plants are restricted by many factors, including UV light, temperature and available nutrients.…”

“…Besides the increase in total number, the distribution among different types of microorganisms changes. The dominating, aerobic, Gram-negative bacteria are replaced by facultative and anaerobic, Gram-positive bacteria of the genera Leuconostoc, Lactobacillus, Pediococcus, Bacillus, and Clostridiurn [15][16][17]21,22]. However, in lactic acid fermentation of plants like alfalfa, ryegrass, cucumbers, carrots, and red beets, it has been shown that Gram-negative bacteria of the family Enterobacteriaceae can be present in high numbers and cause problems such as excessive gas in cucumbers [23] and pectinolytic softening in carrots and beets [12].…”

STREPTOCOCCUS FAECALIS AND STREPTOCOCCUS FAECIUM IN FROZEN VEGETABLES. INCIDENCE AND SURVIVAL AFTER TREATMENTS COMMONLY USED AT THE VEGETABLE FREEZING PLANTS

“…However, the public health significance of the organisms in frozen foods is doubted by many workers, and Splittstoesser (1973) for example, suggested that the enterococci along with other groups become established on equipment surfaces and thus should be considered as part of the "normal" flora of the frozen vegetables. 60 A. Y. SADOVSKI AND AYALA FARBER Mundt et al (1967) and Mundt (1975Mundt ( ,1976 characterized the different streptococcal species naturally occuring on plants and in foods which were frozen or dried and found a great similarity in species distribution in these two sources. He concluded that the major source of this group in the food which was tested is the raw materials and that the variation which sometimes occurred may be attributed to postblanching contamination (Mundt et aZ.…”