Effects of X-ray radiation on Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica and Shigella flexneri inoculated on shredded iceberg lettuce.
The main goal of this investigation was to study the efficacy of X-ray doses (0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 1.5 and 2.0 kGy) on inoculated Escherichia coli O157: H7, Listeria monocytogenes, Salmonella enterica and Shigella flexneri on shredded iceberg lettuce. The second goal was to study the effect of X-ray on the inherent microflora counts and visual color of shredded iceberg lettuce during storage at 4 degrees C for 30 days. Treatment with 1.0 kGy X-ray significantly reduced the population of E. coli O157: H7, L. monocytogenes, Salmonella enterica and S. flexneri on shredded iceberg lettuce by 4.4, 4.1, 4.8 and 4.4-log CFU 5 cm(-2), respectively. Furthermore, more than a 5 log CFU reduction of E. coli O157: H7, L. monocytogenes, S. enterica and S. flexneri was achieved with 2.0 kGy X-ray. Treatment with X-ray reduced the initial microflora on iceberg lettuce and kept them significantly (p < 0.05) lower than the control during storage at 4 degrees C and 90% RH for 30 days. Treatment with X-ray did not significantly (p > 0.05) change the green color of iceberg lettuce leaves. Treatment with X-ray significantly reduced selected pathogens and inherent microorganisms on shredded iceberg lettuce leaves, which could be a good alternative to other technologies for produce (lettuce) industry.
Mahmoud
Barakat S M
BS
Coastal Research & Extension Center, Mississippi State University, 3411 Frederic St, Pascagoula, MS 39567, USA. bm547@msstate.edu
D019453:Escherichia coli O157 / Q000528:radiation effects*; D005511:Food Handling; D005514:Food Irradiation / Q000379:methods*; D018545:Lactuca / Q000382:microbiology*; D008089:Listeria monocytogenes / Q000528:radiation effects*; D050296:Microbial Viability / Q000528:radiation effects; D019779:Salmonella enterica / Q000528:radiation effects*; D012763:Shigella flexneri / Q000528:radiation effects*; D014965:X-Rays