Effects of Storage Conditions of Aspergillus Growth and Aflatoxin Production in Peanuts. A Study in Ghana
| dc.contributor.author | Darko, Clara Bernice | en |
| dc.contributor.committeechair | Mallikarjunan, Parameswaran Kumar | en |
| dc.contributor.committeemember | Frimpong, Emmanuel A. | en |
| dc.contributor.committeemember | Dzisi, Komla Ageko | en |
| dc.contributor.committeemember | Perumpral, John V. | en |
| dc.contributor.committeemember | Balota, Maria | en |
| dc.contributor.department | Biological Systems Engineering | en |
| dc.date.accessioned | 2017-02-14T09:00:16Z | en |
| dc.date.available | 2017-02-14T09:00:16Z | en |
| dc.date.issued | 2017-02-13 | en |
| dc.description.abstract | Peanuts (Arachis-hypogaea) are one of the staples in Ghana, Sub-Saharan Africa, and other developing countries. This leguminous crop is frequently contaminated with aflatoxins, which are secondary metabolites of some Aspergillus fungi, mostly Aspergillus. flavus and Aspergillus parasiticus. Aflatoxins in foods are known to cause liver cancer, stunted growth in children, immune system disorders and economic losses. Aflatoxin contamination of peanuts during storage is worse in the tropics because climatic storage conditions there are almost the same as the optimum conditions for Aspergillus growth: temperature conditions of about 26-43 °C and relative humidity of 62-99%. This study investigated the growth of Aspergillus and the production of aflatoxin in shelled peanuts under varying treatment and packaging conditions. In addition, the appropriate pre-storage treatments and packaging needed to reduce aflatoxin production and to maintain quality of shelled and in-shell peanuts in storage under tropical environments were studied. Another aim was to determine the impact of the switch to hermetic storage on peanut farming and marketing profitability in Ghana. Different peanut treatments, with and without Aspergillus flavus fungi, were packaged in different systems; specifically, polypropylene woven sacks and hermetic packaging. Peanuts were analyzed for fungi growth, aflatoxin production and lipid oxidation (peroxide value and p-Anisidine value). Partial roasting and blanching of peanuts eliminated aflatoxigenic fungi and halted aflatoxin production in stored peanuts, increased the effectiveness of peanut sorting and, hence, helped reduce or eliminate aflatoxin levels along the peanut value chain. Additionally, the results of this study demonstrated that hermetic storage, by suppressing aflatoxin production, has the potential for maintaining peanut quality vis a vis polypropylene woven packaging. Profitability analysis conducted as part of this study revealed that the use of the hermetic storage system would not only improve farmer and trader profits, but also reduce the incidence of various ailments attributed to aflatoxins. | en |
| dc.description.abstractgeneral | Peanuts are one of the staple crops in Ghana, Sub-Saharan Africa, and other developing countries. This crop is frequently contaminated with a special type of molds which produce a poisonous substance called aflatoxin. In foods, it is known to cause liver cancer, stunted growth in children, immune system disorders and economic losses. Aflatoxin contamination during storage in the tropical regions is worst because peanuts are mostly packaged in polypropylene woven sacks and stored under environmental conditions. Unfortunately, climatic conditions promote mold growth and aflatoxin production. In view of this problem, this study was aimed at finding appropriate, affordable and adoptable storage solutions to control fungi growth and aflatoxin production. A portion of the shelled peanuts was partially roasted to kill the molds and to stop aflatoxin production, and then peeled to facilitate the sorting of discolored peanuts which are believed to contain aflatoxins. The partially roasted peanuts and raw ones were packaged in conventional polypropylene woven sacks and hermetic packaging system and stored. It was demonstrated that partial roasting and peeling of peanuts can kill molds and halt aflatoxin production in stored peanuts. Partial roasting increased the effectiveness of peanut sorting and hence, aided in reducing aflatoxin levels along the peanut value chain. Additionally, the results of this study have shown that, compared to polypropylene woven sacks, hermetic storage suppresses mold growth because it eliminates oxygen from the package and results in lower aflatoxin levels and reduces the rate of quality deterioration. Profitability analysis conducted as part of this study revealed that the use of the hermetic storage system would not only improve farmer and trader profitability, but also help reduce the incidence of various ailments that have been attributed to aflatoxins. With the high potential of making additional profits when the hermetic packaging system is adopted, I recommend that local production and marketing of a hermetic storage system be encouraged, along with the active creation of awareness of their benefits in reducing the incidence of aflatoxins. | en |
| dc.description.degree | Ph. D. | en |
| dc.format.medium | ETD | en |
| dc.identifier.other | vt_gsexam:9536 | en |
| dc.identifier.uri | http://hdl.handle.net/10919/75020 | en |
| dc.publisher | Virginia Tech | en |
| dc.rights | In Copyright | en |
| dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en |
| dc.subject | Aflatoxin production | en |
| dc.subject | Aspergillus flavus | en |
| dc.subject | Hermetic storage system | en |
| dc.subject | Polypropylene sacks | en |
| dc.subject | Enterprise budget | en |
| dc.subject | Partial budget | en |
| dc.title | Effects of Storage Conditions of Aspergillus Growth and Aflatoxin Production in Peanuts. A Study in Ghana | en |
| dc.type | Dissertation | en |
| thesis.degree.discipline | Biological Systems Engineering | en |
| thesis.degree.grantor | Virginia Polytechnic Institute and State University | en |
| thesis.degree.level | doctoral | en |
| thesis.degree.name | Ph. D. | en |
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