Evolution of Microbial Flora during Storage of Minimally Processed Herbs

Abstract

Post-harvest operations, handling and storage of fresh herbs may decrease the content of bioactive compounds and increase the microbial contaminants. Minimal processing can extend shelf-life and guarantee microbiological safety.The present study tested the efficacy of minimally processing of parsley ( Petroselinum crispum ), dill ( Anethum graveolens ) and lovage ( Levisticum officinale ) by monitoring the microbiota during cold storage. The three herbs were minimally processed and preserved at 4°C for 12 days. Total plate count and total yeast and mould count were determined during storage and correlated with sensory and biochemical parameters. Parsley had the highest microbial load and lovage the lowest total yeast and mould count throughout the study. Microflora increased significantly during the 12 days of storage. We found that microbial regulations lacked for minimally processed products; thus we could not compare the results with legal limits. Total plate count, total yeast and mould count were correlated negatively with the score for texture and content of total chlorophylls, vitamin C, and total polyphenols. The microbial load was also correlated with the content of volatile aroma compounds. In conclusion, the three minimally processed herbs had a high microbial contamination that increased with storage. So, in the absence of thermal processing, only legal limitations of microflora can guarantee shelf life and food security.