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Lettuce Samples (lettuce + sample)
Selected AbstractsASSESSMENT OF A WASH TREATMENT WITH WARM CHLORINATED WATER TO EXTEND THE SHELF,LIFE OF READY,TO,USE LETTUCEJOURNAL OF FOOD QUALITY, Issue 3 2003J.A. ODUMERU There was a significant difference in psychrotrophic counts (P<0.0001) of warm chlorine (100 ppm) washed lettuce at 47 ± 2C for 30 s, 60 s, and 180 s exposure from days 1 to 10 of storage at 4C compared with cold chlorine (100 ppm) washed lettuce at 4 ± 1C for 30 s. There were no significant differences in psychrotrophic counts between wash treatments of 30 s and 60 s during 17 days storage (P < 0.05). The EN detected initially high levels of volatiles in this group compared with cold treatment. Lettuce samples treated with cold or warm chlorine wash water showed no differences in the presence/absence or levels of Listeria monocytogenes. The warm chlorine washed lettuce samples were rated acceptable upon sensory evaluation up to day 14. [source] Inactivation of Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes on Stored Iceberg Lettuce by Aqueous Chlorine Dioxide TreatmentJOURNAL OF FOOD SCIENCE, Issue 9 2008Yun-Jung Kim ABSTRACT:, Inactivation of Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes in iceberg lettuce by aqueous chlorine dioxide (ClO2) treatment was evaluated. Iceberg lettuce samples were inoculated with approximately 7 log CFU/g of E. coli O157:H7, S. typhimurium, and L. monocytogenes. Iceberg lettuce samples were then treated with 0, 5, 10, or 50 ppm ClO2 solution and stored at 4 °C. Aqueous ClO2 treatment significantly decreased the populations of pathogenic bacteria on shredded lettuce (P < 0.05). In particular, 50 ppm ClO2 treatment reduced E. coli O157:H7, S. typhimurium, and L. monocytogenes by 1.44, 1.95, and 1.20 log CFU/g, respectively. The D10 -values of E. coli O157:H7, S. typhimurium, and L. monocytogenes in shredded lettuce were 11, 26, and 42 ppm, respectively. The effect of aqueous ClO2 treatment on the growth of pathogenic bacteria during storage was evaluated, and a decrease in the population size of these pathogenic bacteria was observed. Additionally, aqueous ClO2 treatment did not affect the color of lettuce during storage. These results suggest that aqueous ClO2 treatment can be used to improve the microbial safety of shredded lettuce during storage. [source] Chromotropic acid-functionalized polyurethane foam: A new sorbent for on-line preconcentration and determination of cobalt and nickel in lettuce samplesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9 2006Valfredo Azevedo Lemos Abstract A chromotropic acid-functionalized polyurethane foam has been developed for use in an on-line preconcentration system for cobalt and nickel determination. The packing material was prepared by covalent coupling of chromotropic acid with the polyurethane foam through an azo group. Co and Ni ions were sorbed in the minicolumn, from which they could be eluted directly to the nebulizer-burner system of a flame atomic absorption spectrometer. Elution of cobalt and nickel from the minicolumn can be accomplished with 0.50 and 0.75 M HCl solutions, respectively. The enrichment factors obtained were 22 (Co) and 27 (Ni), for 60 s preconcentration time, and 57 (Co) and 59 (Ni), if a preconcentration time of 180 s was used. Under the optimum conditions, the proposed procedure allowed the determination of metals with detection limits of 0.43 (cobalt) and 0.52 ,g/L (nickel), respectively, on using preconcentration periods of 180 s. The accuracy of the developed procedure was evaluated by analysis of the certified reference materials NIST 1515 Apple Leaves and NIST 1570a Spinach Leaves. The method was applied to the analysis of lettuce samples. The contents of cobalt in the samples analyzed varied from 0.75 to 0.98 ,g/g. Nickel was not detected in the lettuce samples. [source] | ||||||||||