Metagenomic analysis and keeping quality determination of stored pepper pastes

Pepper paste is a popular condiment used in many cuisines around the world. However, stored pepper paste can deteriorate due to microbial growth and other factors. This study used metagenomic analysis to study the microbial communities in stored pepper pastes produced in a cottage setting, with or without onions labelled ‘A’ and ‘B’, respectively. Microbial count and chemical analysis were also used to determine their keeping quality. The bacterial count in the pepper pastes increased over time. While there was no yeast growth in sample ‘A’, the yeast number in sample ‘B’ increased from 3.0 to 7.0 Log CFU as the day of storage increased. In the selective culturing, there was no Staphylococcus aureus in both samples, growth of enteric bacteria was found in both products towards the end of the storage period, and Salmonella species was only found at some point in ‘B’ (3.0 Log CFU). Proteus (51%) and Pediococcus (48%) were the highest competing genera in ‘A’, while Bacillus (84%) dominated ‘B’ microbiota. The acidity of the samples increased while the nutrients became depleted as storage day increased. At the end of the study, none of the samples without onions remained physically stable. Regardless of any visible deterioration, this study recommends consuming pepper with onions within 60 days and pepper without onions within 30 days.