Monitoring of physicochemical and microbiological parameters during nonnonkoumou (artisanal curdled milk) production in Daloa, Cte dIvoire

Abstract

This study aimed to study physicochemical and microbiological parameters during nonnonkoumou production. A total of 15 samples were analyzed during this study at a rate of 3 samples per fermentation time (T0 h, T6 h, T12 h, T18 h and T24 h). The physicochemical analyses showed a drop in pH (from 7.03 ± 0.028 to 4.59 ± 0.021) during the 24 h of fermentation. The titratable acidity increased from 0.30 ± 0.014% at the start of fermentation to reach the maximum value of 0.88 ± 0.056% at 24 h of fermentation. The sugar level of fermenting milk samples decreased from 10.05 ± 0.071% at the start of fermentation, to 5.15 ± 0.071% at the end of fermentation. The density results showed an addition of water to the milk used for nonnonkoumou production. Microbiological analyses showed a similar growth of lactic acid bacteria and yeasts and molds, but yeasts and molds were absent at the start of fermentation. Aerobic mesophile flora count reached maximum value (7.56 ± 0.81 Log CFU/ml) at 12 h of fermentation. The coliform count increased up to 12 h of fermentation before decreasing and disappearing at the end of fermentation.   Key words: Milk, nonnonkoumou, fermentation, contamination, physicochemical and microbiological analyses.