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Most African foods used in weaning are usually fermented cereals which supplies mainly carbohydrate. Unless these are supplemented with other nutrient sources, they may lead to excessive intake of carbohydrate which might cause malnutrition in growing children. Minimum dietary requirements of a child for protein could be met through fortification with legumes like cowpea, peanuts or soybeans but they contain raffinose family of oligosaccharide (RFOs), which are responsible for gas formation, bloating and flatulence in children. This work aims at using Lactobacillus plantarum and the enzyme αand β-galactosidases it produces, to hydrolyse raffinose to simple sugars and hence improve the raffinose-containing weaning foods. Three strains of L. plantarum obtained from fermented cereal gruels and identified using both classical and molecular methods were selected after screening for their ability to produce these enzymes in abundance. They were used to ferment different combinations of cereals and legumes. The oligosaccharide profile before and after the various pre-treatment methods and fermentation were determined using gas chromatography with flame ionization detector (GC-FID). Data obtained were analysed using ANOVA at p < 0.05. Fermentation for 120 h with L. plantarum reduced the total RFO content of soybeans to different levels in the samples. Losses of 30, 28 and 37% in stachyose, raffinose and verbascose, respectively were observed in the fermented raw samples; 72, 58 and 41% reduction in the fermented cooked samples and 76, 68 and 71% reduction in the roasted samples relative to the untreated samples. The use of galactosidase enzymes by L. plantarum from fermented cereals reduced the raffinose-oligosaccharide profile with simultaneous increase in reducing sugar levels. Adequate weaning foods can be prepared with such and the problem of bloating, gas production and flatulence can be solved by the action of L. plantarum in legume-cereal blends.

The aim of this study was to isolate and screen citric acid producing yeasts using low cost substrates. Thirty three yeast isolates were obtained from pineapple, plantain and sugar cane waste and identified as; Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candida tropicalis, Pichia guilliiermondii, Debaromyces sp., Candida parapsilosis, Candida rugosa, and Candida krusei. Candida tropicalis had zone of clearance of 49±2.1 mm in diameter, Pichia guilliermondii had 40±1.2mm. Saccharomyces cerevisiae produced citric acid with glucose with 105.0 mg/l. C. tropicalis yielded 132.2 mg/l with sodium nitrate. S. cerevisiae and C. tropicalis produced citric acid at pH 6 with 23.70mg/l and 23.80mg/l. P. gulliermondii at pH 4 produced 23.00mg/l. The temperature of 30°C favoured S. cerevisiae and C. tropicalis yielding 40.80mg/l and 39.80 mg/l. After extraction, the yield of the citric acid was 4.231g, 3g of which was recrystallized to yield 2.16g of pure citric acid resulting into 72% recovery. The result indicated that pineapple wastes, plantain wastes and sugarcane cane are potential sources of yeasts that can be used for the production of citric acid. Contribution/Originality: This study contributes in the existing literature by providing basic information for other researchers regarding the isolation and the screening of yeasts for the production of citric acid using low cost substrates, as well as to study the effect of various fermentation parameters on citric acid production. 1. INTRODUCTION Citric acid (2-hydroxy-1, 2, 3-propanetricarboxylic acid) is an intermediate and important commercial product of metabolism and its traces are found in all plants and animals tissues (Kamzolova et al., 2008).Citric acid is a commercially valuable organic acid, widely used in food, pharmaceutical and beverage industries. It has several applications in cosmetic industries as an acidulant flavour enhancer, preservative, antioxidant and emulsifier and chelation agent (Roehr, 1998). Citric acid (C6H8O7) is a natural component and common metabolite of plants and animals. It is the most versatile and widely used organic acid in foods, beverages, detergents and pharmaceuticals. Citric acid is accepted as GRAS (Generally Recognized as Safe) and approved by the Joint FAO/WHO Expert Committee on Food Additives (Dhillon et al., 2011). In its pure form, this citric acid is colourless, soluble in water and solid at room temperature. Due to its functionality and environmental acceptability, it is used in numerous industrial and research applications for chelation, buffering, pH adjustment, and also as a source of energy for controlled bacterial metabolism (Yoo et al., 2004).

Objective: Houseflies are vectors responsible for the mechanical transmission of pathogens acquired from feeding in feces and decayed organic debris. Human consumption of such food without warming could lead to gastroenteritis, a major public health problem. The aim of this research was to evaluate the range of microbial pathogens associated with the external surfaces of fly vectors and to determine the antibiotic susceptibility pattern of the bacterial pathogens. Materials and Methods: A total of 150 houseflies were collected with a sterile net from different parts of Umuahia, Abia State. Their external surfaces were screened for bacteria, fungi, and protozoan parasites in the Microbiology Laboratory of Michael Okpara University of Agriculture, Umudike by standard microbiological procedures. Antibiotic sensitivity pattern of bacterial isolates was carried out by disc diffusion method. Results: The most frequently observed microorganisms were Escherichia coli (22.9%), Klebsiella spp. (16.6%), Staphylococcus aureus (14.6%), Aspergillus spp. (28.3%), Mucor spp. (21.7%), Entamoeba histolytica (32.7%), and Endolimax nana (30.9%). Houseflies from broken sewage had the highest total viable counts and frequency of bacteria, fungi, and parasites. Bacterial isolates from houseflies gotten from health-care facilities showed higher levels of multiple drug resistance to ampicillin and cotrimoxazole. Conclusion: In this study, pathogenic microorganisms were recovered from the external surface of houseflies, the vectoral agents of mechanical transfer of microbial contaminants to exposed food. Most of the microorganisms observed in this study are known pathogens that can cause gastroenteritis which is a public health concern.

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