Year: 2016
Type: dissertation
Abstract: observations for similar African fermented foods.The LAB from emasi and emahewu were characterised a series of assays, Gram stain, catalase reaction, sugar assimilation tests (using API 50 CH test strips) and sequencing the 16S rDNA.Nine morphologically different isolates were identified from emasi, while sixteen (16) were identified from emahewu.It was found that Lactococcus lactis subsp.lactis and Leuconostoc mesenteroides were the common strains in emasi.Lactobacillus plantarum, Lactobacillus paracasei ssp.paracasei and Lactobacillus brevis were also detected.In emahewu, Lactobacillus plantarum were the most common strains, followed by Leuconostoc mesenteroides ssp.mesenteroides, Lb. fermentum and Lb.brevis, Wessella confusa, Lactobacillus acidophilus and Lactococcus lactis.It was concluded that these findings were consistence with other flora of naturally fermented South African milk where the common genera were Leuconostoc, Lactococcus and Lactobacillus.The strains in emahewu compared well with other similar products like ting (South African spontaneously fermented sorghum non-alcoholic porridge) where the main strains were Lactobacillus plantarum, Lactococcus lactis, Lactobacillus fermentum, Lactobacillus rhamnsosus, Weissella cibaria, and Enterococcus faecalis.Sixteen LAB isolates belonging to Leuconostoc lactis, Lactobacillus plantarum, Lb. acidophilus, Weissella confusa, Lactococcus lactis and Leuconostoc pseudomesenteroides were tested for the ability to grow at low pH, in the presence of bile, antibiotics, and for their antimicrobial properties.All of the strains were able to survive at pH 3. Leuconostoc lactis, Lb. plantarum, Lb. acidophilus, L. lactis, Weissella confusa and Leuconostoc pseudomesenteroides grew in the presence of 0.3, 0.5, and 1.0% (w/v) oxgall bile.All of the isolates were sensitivity to ampicillin, amoxicillin and tetracycline.However, Lb. acidophilus was resistant to ampicillin, and a strain of Lb. plantarum (M9) was moderately susceptible to tetracycline.All of the isolates showed resistance to streptomycin, ciprofloxacin and nalidixic acid, while Weissella confusa and Lb.acidophilus were moderately susceptible to ciprofloxacin.A neutral supernatant from each of v the actively growing cultures of the isolates inhibited Salmonella typhimurium ATCC 13311 and Escherichia coli ATCC 25922.The study showed that among the strains tested, Lb. acidophilus Lb. plantarum had properties that could be beneficial to the health of consumers.Occasionally, high numbers of Enterococcus spp have been detected in some Southern African fermented foods.The presence of Enterococcus spp in foods is associated with poor hygienic practices and may indicate a potential risk to consumers who regularly consume the foods.The Enterococcus spp in traditionally fermented milk (emasi), non-alcoholic cereal beverage (emahewu) were isolated on MacConkey agar.Typical colonies were isolated, purified and phenotypically representative strains were identified by sequencing the 16S rDNA.The colony counts in emasi ranged from not detectable to 8.58 log cfu/ml while emahewu ranged from not detectable to 6.72 ± 0.10 log cfu/ml.Five isolates from emasi were identified as Enterococcus durans, Enterococcus hirae, and Enterococcus lactis.One isolate from emasi was Enterococcus durans and Enterococcus lactis.Despite concerns raised by earlier obseravtions on coliform counts, these observations suggest that the fermented foods maybe safe for consumption since the strains recovered are known to be non pathogenic.vi
Author: Protus. Simetende
Language: English
Subfield: Food Science
Domain: Life Sciences
Open Access status: green
Funder: Inyuvesi Yakwazulu-Natali
OpenAlex ID: W2617241585