Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/7/2011
Publication Date: 11/3/2011
Citation: Landa, S., Hernandez, A., Vargas, H., Eslava, C., Lopez, J., Chaidez, Q., Patel, J.R. 2011. Persistence of salmonella typhimurium in nopal cladodes. [abstract]. 13th International COntress on Food Safety and 28th National meeting of Microbiology Hygiene and Toxicology. 100-103. Interpretive Summary:
Technical Abstract: Fresh produce associated outbreaks have increased in the last few years. E.coli O157:H7 and Salmonella have been causative agents of infection in these outbreaks. Fresh produce is consumed raw, and in the absence of terminal kill treatment, it is imperative to understand sources of contamination of fresh produce. We investigated persistence of Salmonella thompson on nopal cladodes. Nine month old nopal plants were used in the study. A kanamycin resistant S. thompson strain was inoculated on mother and secondary nopal cladodes (6 log cfu/ml), and soil was also inoculated with 300 ml strain suspension (8 log cfu/ml) with care to avoid splashing on plant. Cladode and soil were analyzed every 24 h for 15 days for surviving Salmonella populations. Presumptive positive Salmonella colonies on selective media were confirmed by PCR assay. Salmonella populations decreased with time but persisted in soil, and mother cladodes, and secondary cladodes for 14, 14, and 9 days, respectively. However, Salmonella populations on precut secondary cladodes stored at room temperature increased with time and Salmonella were recovered during the entire 15 day sampling period. Effective mitigation strategies should be employed to minimize pre-harvest Salmonella contamination on nopal as this pathogen can persist for longer duration and may cause outbreak of infections.