Effects of pasteurisation on survival patterns of microorganisms and vitamin C retention in kunun-zaki

The effects of pasteurisation on the survival patterns of the microflora as well as vitamin C retention in kunun-zaki fortified with vitamin C was syudied. A laboratory sorghum based kunun–zaki was fortified with 90 mg/l of vitamin C. The content was subjected to pasteurisation at 70oC for different timeintervals ranging from 0 - 30 min. Samples of the beverage were then taken at 5 min intervals during pasteurisation and were analysed for microbial load and residual vitamin C content by 2,6-dichloroindophenol titration method. The results showed that there was a gradual decline in vitamin C retention and steep decline in the microbial load reduction during pasteurisation. The result also showed that at the 20th min of pasteurisation, 80% of microbial isolates had been eliminated leaving only Bacillus Subtilis and Saccharomyces cerevisiae as the surviving organisms. The D70 -value of the most heat resistant organism B. subtilis was found to be 6.5 min

A Survey Of Local Preparation Methods And Quality Of Kunun-Zaki In Two Metropolitan Towns Of Northrn Nigeria

A structured questionnaire survey on ingredients and water sources as well as local production procedures used for making kunun-zaki in Maiduguri and Jos towns of Northern Nigeria was conducted in 2004. Bacteriological and physico-chemical quality of the randomly sampled kunun-zaki in various sites of the two locations were also determined using standard laboratory methods. The results from the respondents showed that the cereal grain, Sorghum bicolour (55%), Zingiber officinale (83.33%) as spicing/flavouring ingredient, malted rice (36.67%) as saccharifying adjunct, Ipomea batatas (31.67%) as sweetening agent and tap water (35%) as source of water (with percentage usage in parenthesis) formed the top most basic raw materials for making kunun-zaki in the two locations. It was also found that kunun-zaki made using hand-dug well water had significantly higher bacteriological loads than those made using bore-hole and tap waters at 5% significance. The total mean plate and coliform counts of the beverage samples obtained from the two location were 8.5 x 106 cfu/ml and 10.52 coliform cells /100ml respectively. The bacterial loads of the beverage samples in the two metropolitan towns did not differ significantly at 5% level of significance. Bacterial pathogens of significance found in the samples included Staphylococcus aureus (83.33%), Bacillus cereus (50.00%) E. coli. (26.50%) and Shigella dysentariae (23.34%) with the percentage occurrences in parenthesis respectively. The mean values of the pH, titratable acidity, specific viscousity and specific density of kunun-zaki were 4.37, 0.04%, 1.58 and 1.05 respectively with no significant differences between the values in the two towns. The significance of the results to good manufacturing practice and consumer health is discussed. Keywords: Kunun-zaki, Sorghum, millet, bacteriological quality, Northern NigeriaGlobal Journal or Pure and Applied Sciences Vol. 14 (4) 2008: pp. 383-38