Investigating the Microbial Quality of Compost Products in Sri Lanka

Abstract: Compost fertilizers offer numerous benefits to living organisms and eco systems and it was confirmed by many more research. However, despite their positive impacts, certain compost fertilizers may pose negative impact on the environment and health due to the composition of pathogenic microorganisms. The issue remains underexplored in existing studies. Therefore, this study analyzed the selected pathogenic microorganisms present in several compost fertilizer products sold in Sri Lankan markets. Both culture-based and molecular-based techniques were used to analyze four compost fertilizers. Gram staining identified both gram-positive and gram-negative bacteria, while morphological analysis of LB and SDA culture media revealed the Aspergillus flavus, Aspergillus niger, Penicillium sp., Fusarium sp., and Candida sp. as fungi, Escherichia coli and Salmonella as bacteria. The PCR analysis confirmed the presence of a few Aspergillus species and the absence of Escherichia coli, Erwinia carotovora & Salmonella. The findings underscore the need for quality control to ensure the safety of compost fertilizers, since Aspergillus sp. detected poses risks to public health and the environment. Continuous evaluation is essential to enhance microbial safety standards.

Compost fertilizers, Aspergillus, Salmonella, Escherichia coli, Erwinia, PCR, Culture media

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