O-80 Microbial analysis of instant rice produced locally in Guyana

Methods: A six-month shelf-life study was conducted to evaluate the microbiological quality of locally produced instant rice and to compare instant parboiled rice with instant white rice. Samples of packaged instant rice consisting of a mixture of local varieties were collected at baseline and at monthly intervals. At each sampling point, total aerobic bacteria and yeasts/molds were enumerated. At six months the microbial quality of the samples were compared with that of imported instant rice. Data was analyzed in SPSS using the analysis of variance (ANOVA) to test for significant differences in microbial counts between rice types and storage time (P=0.05).

Results: Microbial analysis revealed differences in the storage stability of instant rice. For parboiled rice, aerobic bacterial counts increased over time but were not significantly different across storage duration (p=0.156). However, yeast/mold counts increased significantly after five and six months of storage (p=0.015). For instant white rice, aerobic bacteria increased significantly with storage time (p=0.001), reaching the highest level at six months, while yeast/mold counts showed no significant differences (p=0.301). Comparison with supermarket instant rice indicated that locally produced rice had similar microbial loads.

Conclusion: This study indicates that microbiological shelf-life of instant rice is influenced by storage time and rice type. While drying likely reduced initial contamination, it did not prevent microbial increases during the extended storage period. Although locally produced products were comparable to supermarket instant rice with respect to microbial load, the increase during storage supports implementing specific storage conditions, such as moisture control, continuous monitoring throughout the shelf-life, and stricter hygiene and handling practices to ensure safety and quality of locally produced instant rice in Guyana.