Soursops (Annona muricata L.) are highly aromatic fruits with white juicy flesh and are native to tropical North and South America. The ripe fruits are highly perishable, as they become soft and easily bruised. The objectives of the study were to incorporate soursop nectar at 0%, 5%, 10% and 15% in stirred yoghurts and to analyse the products for chemical and sensory quality. A focus group evaluated the initial yoghurts for process modifications. Yoghurts were evaluated on sensory attributes of appearance and colour, body and texture, flavour and aroma, and overall quality. Yoghurts with 10% and 15% soursop nectar had the highest (P<0.05) overall quality scores (12.60/20 and 12.75/20, respectively) but differed (P<0.05) in flavour and aroma from plain yoghurt and 5% soursop yoghurt. Most panelists would consider purchase of 10% and 15% soursop yoghurts over 0% and 5% soursop yoghurts. These yoghurts provided high percentage daily values of zinc, phosphorus and calcium and a good level of protein.

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A method was developed and validated for the determination of ochratoxin A (OTA), a fungal metabolite, in cocoa beans of high fat content. The sample was extracted by blending with a 1% sodium bicarbonate solution (pH 10) followed by ultrasonication, and the sample was defatted by treatment with a flocculant. The defatted sample was purified using immunoaffinity column chromatography, and OTA was detected using HPLC with fluorescence detection. The method was fully optimized, validated, and quality controlled using spike recovery analyses, with recoveries of 89-105% over spiking ranges of 320-2.5 ng/g with CV of analyses generally <10% over 4 consecutive years and an LOQ of 0.66 ng/g in cocoa bean samples. This method overcomes the problems posed by the high fat contents of cocoa and chocolate samples with a high degree of reliability.

A survey of the mycoflora of poultry feeds and feed ingredients revealed a wide range of fungal genera and species, many of which are reported to be mycotoxigenic. Subculturing of randomly selected isolates from three of the most commonly occurring species confirmed their mycotoxin-producing potential. On a brown-rice substrate Aspergillus flaous Link produced on average 56 pg kg-' aflatoxin B,, 53 pg kg-' aflatoxin GI, and 336 pg g-I cyclopiazonic acid. Similarly, subcultured Penicillium citrinum Thom produced 620 pg g-' citrinin, and Aspergillus tamarii Kita 13670 pg g-' kojic acid. The need for a mycological/ chemical approach to mycotoxin monitoring is strongly indicated.