Journal of Pure and Applied MicrobiologyVol. 8 No. 6

Microbiological and Chemical Evaluation of Decomposed Open Pollinated Tomato (Lycopersicon esculentum) Fruits in Storage

Rowland M.O. Kayode and Anthony J. Afolayan*

1Medicinal Plant and Economic Development Research Centre, Department of Botany, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa.

Received on 20 July 2014 and accepted on 10 September 2014

 

ABSTRACT

Tomato spoilage is a major concept of annual revenue wastage in some countries in Africa. In the Northern part of Nigeria, tomato fruits glut has been major problem due to the activities of microorganisms during transportation and storage before sales to the final consumers. This has led to the spoilage of tones of this important fresh produce over decades. Spoilage was initiated in fresh tomato fruit by conditioning them to semi-humid environment and storage at 27?2?C for 14days during which the microbiological and chemical evaluation was examined. Seven organisms were isolated from the decomposed tomato fruits and characterized using genomic DNA extraction, polymerase chain amplification of rRNA and sequence determination. The bacterial isolates were identified on the basis of the 16S rDNA as Bacillius laterosporus, Lactobacillus salivarius and Proteus vulgaris while, yeasts and filamentous fungi were identified on the basis of 26S rDNA as Saccharomyces cerevisiae, Saccharomycopsis fibuligera, Rhodotorula musilaginosa, Aspergillus flavus, Aspergillus niger and Fusarium oxysporum. Three of the identified organisms namely; Bacillus subtilis, Aspergillus niger and Saccharomyces cerevisiae were isolated from the decomposed and control samples. The pH of the decomposing samples showed significant (p<0.05) increase with concomitant decrease in titratable acidity after storage for 8 days. There was significant (p<0.05) increase in the vitamin K of decomposed tomato (8.76 ? 9.45 mg/100g) at the end of 14 days storage when compared control (1.09mg/100g). The carotenoid fractions of the decomposed samples decreased significantly (p<0.05) except malvidin which increased significantly (7.99 - 9.02mg/100g) compared with the values of fresh sample (4.96mg/100g) that was used as control.

Keywords : Tomato, spoilage, microbes, vitamins, carotenoids.