Makgeolli, a traditional Korean alcoholic beverage, is produced from the simultaneous saccharification and fermentation of glutinous rice by microbes introduced through nuruk (fermentation starter). The microbial community in Makgeolli is complex, and changes in the community are important for quality control and product development of Makgeolli. In this study, changes in the microbial community of Makgeolli during brewing were monitored by pyrosequencing. Pyrosequencing of microbes in Makgeolli illustrated dynamic changes in the populations and species of bacteria and fungi during brewing. Saccharomyces, a fungal genus, dominated the fungal community in Makgeolli throughout brewing, and produced alcohol after sufficient production of reducing sugars. As the bacterial genera Pediococcus, Weissella, Lactobacillus and Enterococcus, categorized as lactic acid bacteria, grew in Makgeolli, the pH decreased. The fungal community in Makgeolli was not significantly changed during brewing, but there were dynamic changes in the bacterial community, especially during the first 2 days of brewing.

The prevalence of Bacillus cereus was determined in salad and Kimbab obtained from commercial retailers. Among the 100 salad samples analyzed, 54 samples were negative for B. cereus, whereas the bacterial count was < 10 colony forming units (CFU)/g in 8 samples, < 100 CFU/g in 25 samples, < 1,000 CFU/g in 11 samples, and > 1,000 CFU/g in 2 samples. The mean (standard deviation) was 1.18 log CFU/g (± 0.71 log CFU/g). In Kimbab, B. cereus was isolated from 20 samples; the mean bacterial count was 1.01 log CFU/g (± 0.71 log CFU/g). On the basis of the monitoring data, a statistical sampling plan was determined with the NEWsampleplan program (ICMSF), which was used as an analytical tool. To identify the most suitable sampling plan, the microbial limits (m, M) and the maximum allowable number of sample units yielding unsatisfactory test results (c) were varied, but the number of samples units, n = 5, was fixed. Sampling plans showing an acceptable probability (Pa) over 0.95 were considered suitable. Two plans (A and B) were finally suggested. Parameters for plan A are n = 5, c = 0, m = 1,000, and M = 10,000 and for plan B are n = 5, c = 2, m = 100, and M = 1,000. Interestingly, the latter plan was identical to the microbial sampling plan used in New Zealand. Thus, it was concluded that the suggested plan can be used as a sampling plan that is in line with international standards.

An in vitro study was conducted to examine the effect of addition level of carbohydrates on fermentation characteristics, and bio-hydrogenation of unsaturated fatty acids by mixed rumen bacteria when incubated with soybean oil or flaxseed oil. Four levels(0%, 0.3%, 0.6% and 0.9%, w/v) of the mixed carbohydrates(glucose, cellobiose, soluble starch, 1:1:1, in weight basis) and oil sources(soybean or flaxseed oil, 60 mg in 150 ml culture solution) were added to the mixed solution of strained rumen fluid with artificial saliva(1:4, v/v), and incubated anaerobically for 12 hours at 39 . pH and ammonia-N concentration were lower by increasing the substrate levels at all incubation periods(P<0.05 P<0.001). The propionate proportion increased(P<0.001), but acetic acid and butyric acid decreased(P<0.001) with the substrate level at 6 and 12 h incubations. Oil sources did not influence the proportions of individual VFA. At the end of incubation, the proportions of C18:0 (P<0.01), C18:1 (P<0.001) and trans-11C-18:1 (P<0.01) were reduced but those of C18:2 (P<0.001) and C18:3 (P<0.01) were enhanced by the addition of flaxseed oil compared to addition of soybean oil. The proportions of C18:0 and total CLA were reduced(P<0.01) but those of trans-11-C18: (P<0.05) and C18:2 (P<0.01) were increased with the substrate level when incubated with soybean oil or flaxseed oil. There were interactions(P<0.05) in the proportions of C18:1, C18:2 and C18:3 (P<0.01) between oil source and substrate level. The proportions of cis-9, trans-11-CLA and trans-10, cis-12-CLA tended to reduce with substrate level, although there was no significant difference between treatments.