Effect of Potash Alum on the Mycoflora of Postharvest Spoilage of Solanum lycopersicum L (Tomato) | Chapter 7 | Current Research Trends in Biological Science Vol. 1

Solanum lycopersicum L (Tomato) is one of the most economically attractive and widely consumed vegetables globally. Their high water content, perishability, transport and poor storage system predisposes them to spoilage by a broad spectrum of mycoflora resulting in huge postharvest losses. This study investigates the effect of Potash Alum (PA) on postharvest spoilage of S. lycopersicum L (Tomato). Composite samples of deteriorating tomatoes were subjected to standard mycological analysis from which total fungal colony counts obtained ranged from 1.64×106-5.70×109 CFU/g, and the following species were identified; Aspergillus niger, A. flavus, Fusarium sp, Penicillium sp, Rhizopus stolonifer, Geotrichum candidium and Saccharomyces cerevisiae. In vitro antifungal activity of potash alum (1% (w/v) concentration) was determined on some of the isolates by agar well method (AWM) and diameter of inhibition zone (DIZ) measured using a metre rule. G. candidum had the highest DIZ (9.0mm (29.0%) followed by A. niger (8.0 mm (25.8%) and 7.0mm ( 22.6%) for Fusarium and Penicillium species respectively. R. stolonifer showed no inhibition or zero. pH values increased from 4.35-4.52 whereas TTA values decreased from 0.13-0.07 within 2days of analysis. However, these results indicate that treatment of postharvest deteriorating tomatoes with potash alum prior to consumption would enhance food safety as some of these fungi are known to be spoilage, toxigenic or opportunistic pathogens. So, their presence raises concern on storability as well as public health risks associated with consumption of these fruits. Therefore, production of tomato requires an integrated and multidisciplinary research approach not only to reduce economic loss but also create consumers’ awareness on potential public health hazards of consuming relatively cheaper and pathogen contaminated deteriorating tomatoes.

Author(s) Details

Lawrence O. Amadi
Department of Microbiology, Faculty of Science, Rivers State University, P.M.B. 5080, Nkpolu-Oroworukwo, Port Harcourt, Nigeria and Department of Science Laboratory Technology, School of Applied Science, Ken Saro-Wiwa Polytechnic, Bori, Nigeria.

Dr. (Mrs.) Felicia W. Nmom
Department of Plant Science and Biotechnology, Faculty of Science, Rivers State University, P.M.B. 5080, NkpoluOroworukwo, Port Harcourt, Nigeria.

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In vitro Inhibition of Fusarium by Lactic Acid Bacteria (LAB): Implication of Yam Disease Control for Economic Growth in Nigeria | Chapter 07 | Advances in Applied Science and Technology Vol. 7

Yam is an important crop in Nigeria, where it is produced both as food and cash crop. Fusarium rots of yam are among the most important postharvest pathogens of yam worldwide, causing a lot of postharvest losses in stored yam tubers. Lactic acid bacteria (LAB) lower the pH and create an environment that is unfavorable to pathogens and spoilage organisms. In vitro inhibition of fusarium species by LAB was investigated; mono-culture and multi-cultures were used. The inhibition tests were carried out with pure cultures of LAB and fusarium spp. The pure culture of actively growing Fusarium was inoculated into Potato Dextrose Agar medium aseptically and then incubated at room temperature for 72 h. The diameter of the growing Fusarium was measured, after which less than a loop full of actively growing (18-24 h) LAB isolates were used to inoculate the medium containing the growing Fusarium at a known distance in the same plate. The whole set up was incubated at 300C and inhibition zones on Fusarium by the LAB were observed 24 hourly for 96 h. The tests were carried out for mono-culture and multi-cultures in triplicate. The inhibition zone ranged from 43 to 100% in mono-culture plates and from 40 to 113% in multi-culture plates. The slightly larger inhibition in the multi-culture plate may be due to much pressure on the Fusarium. Hence LAB may be used to control rot caused by Fusarium in in stored yam, which can improve yam tuber storage for better economic growth.                   

Author(s) Details

R. M. Omodamiro
Department of Postharvest Technology Programme, National Root Crops Research Institute, Umudike, Nigeria.

P. C. Ojimelukwe
Department of Food Science and Technology, Micheal Okpara University of Agriculture, Umudike, Nigeria.

Dr. R. Asiedu
Yam Barn Unit, International Institute of Tropical Agriculture, Ibadan, Nigeria.

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