Elimination of bacterial isolates from Jollof rice meal by irradiation and chilled storage

Abstract

The radiation sensitivity of three bacterial isolates (Escherichia coli, Staphylococcus aureus and Salmonella parathyphi B) on jollof rice meal (JRM) was determined. Based on the calculated D10 values, challenge testing of the isolates with irradiation (0, 2 and 3 kGy) was conducted on JRM followed by chilled (3-5C) storage (0, 7, 14, 21 and 28 days). Calculated D10 values of E. coli, S. aureus and S. parathyphi B were 0.173, 0.260 and 0.285 kGy, respectively. Linear correlation coefficients of the regression lines were all >0.910 and highly significant (P < 0.01). A dose of 2 kGy reduced the population of E. coli by 6 log cycles and those of S. aureus and S. parathyphi B by 4 log cycles. A dose of 3 kGy eliminated all the isolates from the JRM during the 28-day storage period and is therefore adequate to eliminate pathogens from JRM to enhance microbiological quality. © 2008, The Author(s).