Properties of “nono,” a Nigerian fermented milk food

Traditional and Artisanal Beverages in Nigeria: Microbial Diversity and Safety Issues

A review of up to 90 articles on the microorganisms associated with important artisanal or traditional beverages in Nigeria was carried out. This resulted in an overview of the prevalent microorganisms associated with soymilk, nono (fermented cow milk), tiger nut milk, yoghurt, kunu, zobo, palm wine and the local beers pito and brukutu. The bacteria genera, namely Bacillus, Escherichia, Lactobacillus, Staphylococcus, and Streptococcus, were detected in all nine beverages. On the contrary, this survey resulted in finding that the genera Saccharomyces, Aspergillus, Candida, and Penicillium were the eukaryotic microorganisms isolated in all beverages. The occurrence of fungal isolates, which can be responsible for producing mycotoxins, is a concern and shows the need for post-production tests. Overall, there is a low prevalence of bacteria associated with hygiene, especially the Escherichia genus in alcoholic beverages such as palm wine, pito and burukutu, which may be due both to a low acidity and high ethanol content. However, the prevalence of hygiene indicator genera was higher in nonalcoholic drinks, probably because of incorrect practices during processing. The magnitude of the production and sales of unregulated local beverages in Nigeria has reached the stage where significant regulation and food safety standards are required to safeguard public health. An opportunity exists to monitor and characterize the microbial flora of the artisanal beverages using molecular methods at all stages of production and storage.

Assessment of the physicochemical and bacteriological qualities of Nono - a fermented cow milk

Nono is a spontaneously fermented yoghurt-like milk product consumed is a staple food commodity in parts of the Sub-Saharan West Africa. Nono is usually consumed along with 'Fura' as 'Fura da Nono' in Nigeria. Studies on physicochemical and bacteriological qualities were carried out on samples of Nono obtained from 5 different sources in Ado-Ekiti, Nigeria. The Nono samples were found to be nutritious, containing moderate levels of ash, crude fat, crude protein and carbohydrate. The pH of the Nono samples was relatively low (4.04 ±0.04), while the density and specific density were close to that of distilled water at room temperature. Total aerobic plate count of Nono samples was 1.8 ±0.02 × 106 CFU.mL-1. A total of 15 bacteria species namely Eubacterium nodatum, Bacillus subtilis, Chromobacterium violaceum, Propionibacterium acnes, Amycolatopsis benzotilytica, Tropheryma whipplei, Moraxella catarrhalis, Campylobacter gracilis, Neisseria sicca, Vibrio natiensis, Photobacterium damselae, Corynebacterium kutsceri, Corynebacterium xerosis, Lactobacillus fermentum and Lactobacillus casei were isolated from the Nono samples. The gram-positive bacterial isolates were resistant to all antibiotics tested with the exception of Erythromycin where 40% susceptibility was obtained, while the gram-negative bacteria showed high resistance to the tested antibiotics, but with 80% susceptibility to Ofloxacin. The nono samples were observed to exhibit antibacterial activity against cultures of Salmonella typhimurium ATCC 14028, Escherichia coli ATCC 29929 and Staphylococcus aureus ATCC 29293. Most of the bacteria isolated were of less public health importance, but the high prevalence of multi-drug resistance is of great concern.

Characterization of dominant microbiota of a Ghanaian fermented milk product, nyarmie, by culture- and nonculture-based methods

AIMS

To characterize the predominant micro-organisms in a Ghanaian traditional fermented dairy product, nyarmie, made from cows' milk, using both culture- and nonculture-based methods.

METHODS AND RESULTS

Samples of nyarmie were analysed from three production sites in Accra, by determining the counts on selective culture media. The microbial diversity occurring in nyarmie was also evaluated by 16S/18S ribosomal DNA PCR amplification and denaturing gradient gel electrophoresis. Results showed that nyarmie contained lactococci and lactobacilli in the range of 10(8) and 10(10) CFU ml(-1), respectively, and yeasts at around 10(7) CFU ml(-1). The pH ranged between 3.49 and 4.25. The predominant lactic acid bacteria (LAB) in nyarmie were Leuconostocmesenteroides ssp. mesenteroides, Streptococcus thermophilus, Lactobacillus delbrueckii ssp. bulgaricus, Lact.helveticus, Lact. delbrueckii ssp. lactis and Lactococcus lactis, while Saccharomyces cerevisiae was the predominant yeast species. Lactobacillus delbrueckii ssp. delbrueckii was not detected by cultivation but its predominance was revealed by PCR-DGGE analysis.

CONCLUSIONS

The flora in products from different producers varied in the LAB composition present and may result in variations in product quality.

SIGNIFICANCE AND IMPACT OF THE STUDY

Development and use of starter cultures for nyarmie may be beneficial in improving the consistency of product quality.

The interaction between yeasts and bacteria in dairy environments

The general environment from which raw dairy products originate and the microbiological quality of the products in its processed state inevitably admit yeast growth and spoilage. Only part of the primary microflora survives under the selective pressures exerted by the intrinsic and extrinsic biotic factors present, processing procedures and preservatives. Yeasts that possess the proper physiological attributes to counteract the specific ecological determinants will be favored. Eventually, a particular yeast community will develop, and if the environmental factors permit, this characteristic yeast community will result in a specific association contributing positively or negatively to the final product. The association that develops between yeasts and bacteria is governed by specific key properties selecting for a few predominant yeasts. These yeasts may either stimulate or inhibit normal bacterial growth. The extent to which interaction between yeasts and bacteria contribute to the final product is discussed.