A survey was conducted in Nairobi, Nyanza and Western provinces in Kenya between March and July 2009 with 1263 peanut products sampled out of which 705 samples underwent microbial analysis. The study aimed at determining the incidence of fungal species e emphasis on Aspergillus section Flavi e associated with peanut products. A 0.5 kg representative sample was obtained from each surveyed vendor and the colony forming units (CFU) of fungal species determined. The samples were also analyzed for total aflatoxin level while isolates of Aspergillus flavus and Aspergillus parasiticus were screened for production of aflatoxin B1, B2, G1 and G2. Eight fungal species were detected in the samples and were in decreasing order of CFU/g of sample: A. flavus S-strain (467), A. flavus L-strain (341), Penicillium spp. (326), Aspergillus niger (156), Aspergillus tamari (27), Aspergillus alliaceus (21), A. parasiticus (10), and Aspergillus caelatus (5). The overall incidence of A. flavus S-strain in samples from Nairobi was 92 and 1425% higher than samples from Nyanza and Western regions, respectively. The combined incidence of A. flavus and A. parasiticus was varied significantly (p 0.05) with peanut product: peanut flour (69%), shelled raw peanuts (53%), spoilt peanuts (49%), boiled podded peanuts (45%), podded peanuts (39%), peanut butter (31%), fried peanuts (22%) and roasted peanuts (20%). Seventy three percent of A. flavus and A. parasiticus isolates produced at least one of the aflatoxin types, with 66% producing aflatoxin B1. The total aflatoxin level among peanut products ranged from 0 to 1629 mg/g; and there was a positive correlation (r ¼ 0.2711) between the incidence of A. flavus and A. parasiticus, and total aflatoxin level. The high incidence of aflatoxin producing fungi in peanuts traded in Kenyan markets implies a risk of aflatoxin contamination, highlighting the need for stakeholders to promote sound practices at all stages of the peanut value chain in order to minimize market access by non-complying products.
Peanut kernels of Homabay Local, Valencia Red, ICGV-SM 12991 and ICGV-SM 99568 cultivars were stored for six months in jute, polypropylene and polyethylene bags to assess the effect of storage bags, temperature and R.H. on fungal population and aflatoxin contamination. Moisture content (M.C.), fungal population and aflatoxin levels were determined before storage and after every 30 days during storage. Isolates of Aspergillus flavus and A. parasiticus were assayed for production of aflatoxin B1, B2, G1 and G2. The correlation between MC, population of A. flavus and A. parasiticus and aflatoxin levels in peanuts was also determined. Six fungal pathogens were commonly isolated from the peanut samples and occurred as follows in decreasing order: Penicillium spp. (106.6 CFU/g), A. flavus L-strain (4.8 CFU/g), A. flavus S-strain (2.9 CFU/g), A. niger (2.6 CFU/g), A. parasiticus (1.7 CFU/g) and A. tamarii (0.2 CFU/g). The overall population of A. flavus L-strain was 66% higher than that of A. flavus S-strain. Ninety one percent of A. flavus and A. parasiticus isolates produced at least one of the four aflatoxin types assayed, with 36% producing aflatoxin B1. Total aflatoxin levels ranged from 0 -47.8 µg/kg with samples stored in polyethylene and jute bags being the most and least contaminated, respectively. Eighty nine percent and 97% of the peanut samples met the EU (≤ 4 µg/kg) and Kenyan (≤ 10 µg/kg) regulatory standards for total aflatoxin, respectively. Peanuts should be adequately dried to safe moisture level and immediately packaged in a container -preferably jute bags -which will not promote critical increases in fungal population and aflatoxin contamination.
The use of hydrogenated rapeseed oil as a carrier for conidia of the entomopathogenic fungus Beauveria bassiana (Bals) Vuill was investigated as part of a research programme on the control of the larger grain borer, Prostephanus truncatus (Horn). Melting the oil, which is solid at temperatures below 32°C, allows the incorporation of materials such as aggregation pheromones and conidia; sudden cooling produces solid fat pellets.In attraction tests conducted with pellets containing P truncatus aggregation pheromone, signi®-cantly higher numbers of beetles were attracted to pellets containing pheromone at a concentration of 4 ml litre À1 compared to control pellets for at least four weeks when held in Petri dishes in the laboratory and for at least six weeks when pellets held in insect traps were exposed to outside conditions. The attraction was retained over a period of storage in glass bottles; pellets stored in the freezer or incubator (at À10°C or 27°C) attracted beetles according to the pheromone level for the duration of the work (14 and 13 months respectively). When pheromones and conidia were incorporated into the same pellets they could be stored in a freezer or refrigerator retaining over 80% viability after 51 weeks; those stored in an incubator at 27°C showed signi®cantly lower germination at 20.7±27.2% after the same time. There was an indication that the pheromone caused a slight reduction in the viability of conidia, although this may have been just a slight delay in the speed of germination.Rapid dose transfer from pellets with conidia with and without the addition of pheromone was demonstrated. Insects were exposed to pellets for 24 hours and 96±100% mortality was observed in treatments containing conidia within six days of exposure.
Using memory work, a group of eight adults in a university setting wrote, shared, and theorized memories of life challenges we experienced. In this study, we have adapted and refined memory work as a method, and we model this by presenting and examining a comprehensive case example of memory work. Our memories were of four main types: stories of dangerous events, the unruly body/self, leaving home/returning home, and negotiating social relationships. Processes of writing, performing, witnessing, and theorizing led us to identify ruptures and turning points that revealed ways in which we have been culturally inscribed as well as our agency in integrating social discourses into our identity. Our results point to the value of collaborative autobiography as a route to insight, a way to build community, and a means to democratize research.
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