Grading of fermented and dried cocoa beans using fungal contamination, ergosterol index and ochratoxin a production.

Sixty four samples of cocoa beans replicated in quadruplicates were collected from five warehouses from southwest Nigeria and examined for fungal loads, ergosterol and ochratoxin A The levels of all the variables obtained were further used as indices for cocoa grading into food quality, FoQ (erg < 5 mg/kg; OTA < 1 µg/kg), feed quality, FeQ (erg = 5~10 mg/kg; OTA in the range of 1.1~3.11 µg/kg), Screen for mycotoxin, SFM (erg = 10~20 mg/kg; OTA from 3.12 µg/kg and above) with fuel quality, FuQ having erg > 20 mg/kg and OTA > 6.12 µg/kg. Using these ergosterol indices, 18.75% of the cocoa beans examined was classified with the FoQ, 18.75% with the FuQ while 31.25% was classified with both the FeQ and the SFM, respectively. In conclusion, ergosterol can be used as a rapid index to grade fermented, dried cocoa beans meant for export.

Inhibitory effect of Garcinia kola on lipid peroxidation in rat liver homogenate.

Garcinia kola, (a herb grown in Nigeria; calorific value 358.54 k.cal/100 g) inhibited in vitro lipid peroxidation of rat liver homogenate in a dose dependent manner. The inhibitory activity of G.kola was not affected by heating (100 degrees C/10 min). The antioxidant component of G.kola was soluble in aqueous and ethanolic media. The active component(s) in G. kola responsible for its inhibitory activity on lipid peroxidation is tentatively identified as isoflavones.

Influence of sundrying on the chemical composition, aflatoxin content and fungal counts of two pepper varieties--Capsicum annum and Capsicum frutescens.

Samples of sundried, matured red pepper, Capsicum annum with a moisture content (MC) of 12.7-26.8 percent had on dry weight basis, vitamin C, 5.0-6.4 mg/100 g; crude protein, 0.8-1.2 percent; total soluble solids, 3.3-4.1 percent, and fungal counts of log 4.4-4.5/g. Ordinary matured red C. annum had MC, 75.7-78.2 percent vitamin C, 36.1-38.5 mg/100 g; crude protein, 2.4-2.8 percent; total soluble solids, 9.3-9.9 percent and fungal count of log 3.32-3.39/g. Sundried matured red C. frutescens had corresponding values of 9.4-18.7 percent; 5.8-6.3 mg/100 g; 0.8-1.1 percent; 0.9-2.6 percent and log 3.2-3.4/g. No aflatoxins were detected in sundried, matured red C. frutescens, but aflatoxin B1 values obtained from C. annum varied from non-detectable to 2.2 micrograms/kg. Dominant fungi isolated from C. annum and C. frutescens were Rhizopus oryzaze, Aspergillus niger, A. flavus, Geotrichum candidum and Saccharomyces spp.

Influence of grain quality, heat, and processing time on the reduction of aflatoxin B1 levels in 'tuwo' and 'ogi': two cereal-based products.

During the production of 'tuwo' from laboratory-contaminated corn (AFB1:150 mcg/kg) and sorghum (AFB1:87.5 mcg/kg) grains, reductions in the aflatoxin-B1 levels of pastes boiled for 30 min and 60 min were found to be 68.0% and 80.8%, respectively. In the preparation of 'ogi' from contaminated corn and sorghum grains, reductions of about 72.5% and 71.4%, respectively, were obtained after fermentation at ambient conditions. Reconstitution of 'ogi' paste into a porridge (akamu) considerably reduced the AFB level.

Production, nutritional profiles and storability of 'aadun' and 'kokoro': two corn products.

'Aadun' and 'kokoro' were produced from maize grains by processes involving roasting, kneading, spicing, and frying. 'Aadun' with a moisture content (MC) of 12.5%, pH 5.3 had the following composition: crude protein, 7.49%; fat, 28.5%; total carbohydrate, 60.0%; ash, 3.0% and energy value, 3,600 kcal/kg whilst 'kokoro' with a MC of 16% and pH 5.1 had, respectively: 6.42%; 22.9%; 66.6%; 2.84% and 3,550 kcal/kg. Whilst 'aadun' and 'kokoro' stored under ambient conditions (28 +/- 2 degrees C; 75-80% RH) became mouldy within 7 days, samples treated with 1% butyl paraben did not develop off-colour and mouldiness.

Nutritional profile and antimicrobial spectrum of the spice Aframomum danielli K. Schum.

The spice, Aframomum danielli, on a wet weight basis with a moisture content of 10.5%, protein content of 8.2% (dry matter basis) and caloric value of 469.7 kcal/100 g, contains in varying amounts, minerals like calcium, magnesium, sodium, manganese, phosphorus, zinc and copper. Amino acids found in varying concentrations in A. danielli include L-Threonine, L-Serine, L-Valine, L-Proline, L-Glutamic acid, glycine, L-Leucine and L-Lysine. Using minimum inhibition zone of 20-22 mm in diameter, A. danielli inhibited the growth of Salmonella enteriditis, Psudomonas fragi, Pseudomonas fluorescens, Proteus vulgaris, Streptococcus pyogenes, Staphylococcus aureus, Aspergillus flavus, A. parasiticus, A. ochraceus and A. niger. The minimum concentration (MIC) determined for Klebsiella pneumoniae and Pseudomonas aeruginosa was 1 in 320 whilst the MIC for S. aureus was 1 in 8,000.

Effect of processing on the mycoflora and aflatoxin B1 level of a cassava-based product.

Cassava bread was prepared by pre-gelling, battering and baking cassava flour to which were added, in moderate amounts, sugar, yeast solution and edible oil. Baking was at 215 degrees C for 40 min. No mould was isolated from the cassava bread and the mean value of aflatoxin B1 (AFB1) for the three subsamples of cassava bread was 0.03 microgram/kg. The cassava tuber (Manihot esculenta Crantz), which was used for the production of cassava bread had an initial AFB1 level of 1.91 micrograms/kg and the dominant mycoflora were Penicillium oxalicum, Aspergillus flavus, Fusarium spp and some unidentified fungi.

Effect of sample pretreatments on the storability of ground melon 'egusi'-Colocynthis citrillus L.

In the maintenance of shelf-stability, nutritional and organoleptic properties of ground melon 'egusi'-Colocynthis citrullus L., vacuum-packaged samples were found to be better than unpackaged samples and samples treated with 0.2% butylated hydroxyanisole (BHA) and 0.02% BHA + 0.045% sodium metabisulphite. After 56 days at 35 degrees C, stored samples showed significant differences (P < or = 0.01) in chemical composition peroxide value (PV), fungal counts and organoleptic attributes. Lipid oxidation and, to a lesser extent, fungal deterioration were responsible for the spoilage of stored ground melon kernel. The dominant fungal flora isolated from stored samples were of the genera Penicillium, Botryodiplodia, Rhizopus and Aspergillus.

Decrease of growth and aflatoxin production in Aspergillus parasiticus caused by spices.

Non-commercial spices and herbs Tetrapleura tetrapetra, Triumfetta cordifolia, Garcina kola, Monodora myristica and Xylopia aethiopica at 0.08 to 0.32% (w/v) decreased the mycelial weight of Aspergillus parasiticus NRRL 2999 in yeast extract/sucrose broth by up to 68%. Aflatoxin production, monitored with ELISA, was most effectively decreased, from 97 to 23 µg/ml, when the extract of G. kola was added at 0.32% (w/v).

Effects of sodium metabisulphite, hydrogen peroxide and heat on aflatoxin B1 in lafun and gari--two cassava products.

Sodium metabisulphite and hydrogen peroxide alone or in combination with heat (50-70 degrees C) were found to be effective in degrading aflatoxin B1 (AFB1) in lafun and gari. Hydrogen peroxide (H2O2) at a concentration of 3% in the aqueous phase gave a 12.5% degradation of aflatoxin B1 in lafun and at 50 degrees C, degradation levels of 25% and 50% were obtained with 6.0 and 9.0% H2O2, respectively. When sodium metabisulphite was applied during the production of gari (a fermented cassava product heated to 50-70 degrees C during production) AFB1 degradation levels were found to be 65.8%, 60.9%, 41.5% and 36.6%, respectively, for sodium metabisulphite levels of 1.0%, 0.8%, 0.5% and 0.3%.

Urinary tract pathogens common amongst the inhabitants of a state capital, south west Nigeria.

In the course of a survey of urine samples collected over a period of 12 months from male and female patients of different socio-economic backgrounds in Ibadan, Esch. coli, Klebsiella spp. Pseudomonas aeruginosa, Proteus spp., Staphylococcus aureus and Candida albicans were the most common pathogens isolated. The bacteria were commonly sensitive to the cephalosporins, kanamycin, ampicillin and cotrimoxazole in decreasing order of sensitivity.

Comparative characteristics of Staphylococcus sciuri, Staphylococcus lentus and Staphylococcus gallinarum isolated from healthy and sick hosts.

Of 136 strains of coagulase-negative staphylococci isolated from healthy and sick human beings, goats, sheep, antelope and other animals, 88 (64.7%) were Staphylococcus sciuri and 35 (25.7%) were S. lentus and the remainder Staphylococcus gallinarum. The strains of S. sciuri were isolated from humans with boils and wounds, goats with pestes des petits ruminants (PPR) and dogs with nasal discharge. One isolate of S. gallinarum came from a fowl with chronic respiratory disease and 11 others were isolated from goats. The characteristics of S. sciuri, S. lentus and S. gallinarum isolated from different sources were similar.

Characteristics of staphylococci isolated from man, poultry and some other animals.

Of 281 strains of staphylococci isolated from man and animals 36 (12.8%) were coagulase-positive and 245 (87.2%) were coagulase-negative. Staphylococcus aureus and Staph. intermedius were the commonest coagulase-positive staphylococci isolated from the hosts examined. Of the 20 strains that remained unclassifiable, 14 were isolated from sheep and goats.

Characteristics of some unclassifiable strains of staphylococci isolated from goats and sheep.

Fourteen strains of catalase-positive, Gram-positive and coagulase-negative cocci that were sensitive to 20 micrograms/ml of furazolidone were isolated from goats and sheep. Two of the strains had glycerol with glucose teichoic acids whilst another possessed glycerol, glucose, glucosamine and acetylglucosamine teichoic acids. Six strains had peptidoglycan type L-Lys-Ala-Gly4 peculiar to Staphylococcus sciuri and Staph. lentus but other phenotypic characters were different from those of Staph. sciuri and Staph. lentus. The guanine plus cytosine (G + C) content of the DNA determined for three of the strains examined ranged from 32.9-34.6 mol %. The coagulase-positive staphylococcal strain of caprine origin examined had glycerol and glucosamine teichoic acids in addition to peptidoglycan type L-Lys-Gly5-6. The characteristics of the strains of staphylococci described herein are different from those already described in the literature.

Serological characteristics of coagulase-positive staphylococci isolated from man and animals.

A simplified method allowed Staphylococcus aureus, Staph. intermedius and coagulase-positive Staph. hyicus subsp. hyicus isolated from humans, dogs, monkey, sheep, poultry, rabbits, giant rats (Cricetomys gambianus) and other animals to be serotyped. The nine coagulase-positive staphylococcal strains of human origin possessed thermolabile and thermostable agglutinogens. Two strains of Staph. intermedius of human and canine origins examined had agglutinogen K1K2. The three Staph. aureus strains isolated from African giant rats (Cricetomys gambianus) had agglutinogens a5 and P common to them. The Staph. aureus strain isolated from a monkey belonged to serotype b1, c1, o and the caprine strain of Staph. hyicus subsp. hyicus was serotype a5, c1.

Identification of coagulase-negative staphylococci from farm animals.

The species identify of 661 strains of coagulase-negative staphylococci isolated from the skin and nares of cattle, pigs, poultry, goats and sheep was determined. They belonged either to the novobiocin-sensitive species Staphylococcus hyicus, Staph. simulans, Staph. epidermidis, Staph. haemolyticus and Staph. warneri or to the novobiocin-resistant species Staph. sciuri, Staph. lentus, Staph. xylosus, Staph. cohnii, Staph. saprophyticus and Staph. gallinarum; twenty-one strains remained unidentified. The staphylococcal flora of the farm animals studied differed markedly from that associated with man; several species which do not occur in man were isolated and novobiocin-resistant strains, which occur infrequently in man, were present in large numbers in animals. Two simplified schemes for the identification of staphylococci from farm animals and man are presented.

Biotypes, serotypes and phage types of caprine strains of Staphylococcus aureus.

Nine of 11 caprine strains of Staphylococcus aureus examined belong to biotype C. They were typable serologically using antisera developed for typing human strains of Staphylococcus aureus. H2 was found to be the dominant thermostable antigen whilst 1 and 0 were the most common thermolabile antigens. Some strains possessed protein A and poly A beta (beta-glucosaminyl ribitol teichoic acid). Phage typing of the strains was achieved with an international set of phages for typing human strains of Staphylococcus aureus and they belong to phage groups II, and the mixed group.

Biochemical characterization of staphylococci isolated from goats.

Caprine strains of staphylococci show strong and early results in carbohydrate fermentation tests. Their ability to produce DNase and acetoin is weak but they possess a reasonably high degree of phosphatase activity. All the 82 isolates of Staphylococcus aureus isolated from clinically healthy and sick goats produced acid from D-(+)-glucose aerobically at 37 degrees C within 24 h, 98.8% fermented both D-mannitol and maltose, 98.7% fermented sucrose, and 81.7% fermented D-(+)-xylose with acid production, but none fermented L-sorbose. Of the ten coagulase-negative staphylococci characterized to be of animal origin, three produced DNase, but none fermented dulcitol and L-sorbose. All fermented D-(+)-glucose, maltose and D-mannitol, eight fermented D-(+)-xylose and D-sorbitol with acid production. Whilst other coagulase-positive and coagulase-negative staphylococci showed different antibiotic susceptibility patterns, the ten coagulase-negative staphylococci characterized to be of animal origin showed similar antibiotic susceptibility patterns.

Bovine fascioliasis in Nigeria--intercurrent parasitic and bacterial infections.

The bacterial and parasitic infections associated with field cases of bovine fascioliasis due to Fasciola gigantica were investigated; 47.6% of infected cattle had blood parasites, 61.9% had faecal-borne parasites and 85.8% had positive bacterial isolates in the bile in contrast to 13.3% with blood parasites, 71.1% with faecal-borne parasites and 28.9% positive for bile bacteria among uninfected cattle. Trypanosoma spp., Babesia, Paramphistomum and Schistosoma were the most commonly found parasites associated with fascioliasis. On the other hand Staphylococcus pyogenes, Escherichia coli and mixed infections of these with other Enterobacteriaceae were the common bacteria isolated from the bile of infected cattle. The parasitaemia of Babesia was significantly higher in infected than uninfected cattle but there was no significant difference in strongyle egg count between the 2 groups of cattle.