Microbiological comparison of visibly dirty and visibly clean mature green tomatoes before and after treatments with deionized water or chlorine in model overhead spray brush roller system


  • Oleksandr Tokarskyy Ternopil State Medical University, International Students”™ Faculty, Department of Medical Biochemistry, Maidan Voli 1, 46001, Ternopil, Ukraine, Tel: +380964102536
  • Mykhaylo Korda Ternopil State Medical University, Department of Medical Biochemistry, Maidan Voli 1, 46001, Ternopil, Ukraine, Tel: +380352524492 https://orcid.org/0000-0002-6066-5165




tomatoes, cleanness, natural microflora, overhead spray brush roller system


The purpose of the current study was to compare natural microflora counts of mature green tomatoes as influenced by visual cleanness, and investigate ability of chlorine sanitizer to reduce different groups of natural microflora on the surface of tomatoes using overhead spray brush roller system. We hypothesized that natural microflora might not be equally affected, with vegetative Gram negative bacteria being more sensitive and soil-related Gram positive sporoforming bacilli and molds more resistant. Microflora from untreated visibly clean and visibly dirty tomatoes, as well as from visibly clean tomatoes after 30 seconds deionized water or 100 ppm chlorine treatments, was recovered and spread plated on Tryptic Soy agar, MacConkey agar, and acidified Potato Dextrose agar. Microflora from untreated and chlorine-treated tomatoes was non-specifically enriched and plated on agar with chlorine paper disc diffusion assay applied to check for inhibition zone differences. Interestingly, there was no significant difference in plate counts between visibly clean and dirty tomatoes (p >0.05). Chlorine was more effective than water alone to reduce microbial counts on tomatoes for all microbiological media tested. Based on similar relative reductions of microorganisms in each group, it was concluded that chlorine may have no preferential kill for investigated groups of microorganisms. High counts remaining after treatment with chlorine solution suggested possibility of resistant microbial biofilm formation on the surface of tomatoes.


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Allende, A., McEvoy, J., Tao, Y., Luo, Y. 2009. Antimicrobial effect of acidified sodium chlorite, sodium chlorite, sodium hypochlorite, and citric acid on Escherichia coli O157:H7 and natural microflora of fresh-cut cilantro. Food control, vol. 20, no. 3, p. 230-234. https://doi.org/10.1016/j.foodcont.2008.05.009

Chang, A. S. 2011. Evaluation of overhead spray-applied sanitizers for the reduction of Salmonella on tomato surfaces: master of science thesis. Gainesville, FL, USA : University of Florida. https://doi.org/10.1111/j.1750-3841.2011.02486.x

Chang, A. S., Schneider, K. R. 2012. Evaluation of overhead spray-applied sanitizers for the reduction of Salmonella on tomato surfaces. Journal of food science, vol. 71, no. 1, p. M65-M69. https://doi.org/10.1111/j.1750-3841.2011.02486.x

Davidson, P. M., Harrison, M. A. 2002. Resistance and adaptation to food antimicrobials, sanitizers, and other process controls. Food technology, vol. 56, no. 11, p. 69-78.

De, J., Li, Y., Sreedharan, A., Goodrich Schneider, R. Gutierrez, A., Jubair, M., Danyluk, M. D., Schneider, K. R. 2018. A three-year survey of Florida packinghouses to determine microbial loads on pre- and post-processed tomatoes. Food Control, vol. 86, p. 383-388. https://doi.org/10.1016/j.foodcont.2017.11.036

Duran, G. M., Marshall, D. L. 2005. Ready-to-eat shrimp as an international vehicle of antibiotic-resistant bacteria. Journal of food protection, vol. 68, no. 11, p. 2395-2401. https://doi.org/10.4315/0362-028X-68.11.2395

Dychdala, G. R. 2001. Chlorine and chlorine compounds. In: Block S. S. Disinfection, sterilization, and preservation. 5th ed. Philadelphia, PA : Lippincott Williams and Wilkins. p 135-158. ISBN-13: 978-0683307405.

Fatica, M. K., Schneider, K. R. 2009. The use of chlorination and alternative sanitizers in the produce industry. CAB Reviews: perspectives in agriculture, veterinary science, nutrition and natural resources, vol. 4, no. 52, p. 1-10. https://doi.org/10.1079/PAVSNNR20094052

FAOSTAT. 2017. Food and Agriculture Organization of the United Nations. Commodities by country. Countries by commodity. Available at: http://www.fao.org

Gereffi, S., Sreedharan, A., Schneider, K. R. 2015. Control of Salmonella cross-contamination between green round tomatoes in a model flume system. Journal of food protection, vol. 78, no. 7, p. 1280-1287. https://doi.org/10.4315/0362-028X.JFP-14-524

Gil, M. I., Selma, M. V., López-Gálvez, F., Allende, A. 2009. Fresh-cut product sanitation and wash water disinfection: problems and solutions. International journal of food microbiology, vol. 134, no. 1-2, p. 37-45. https://doi.org/10.1016/j.ijfoodmicro.2009.05.021

Jay, J. M. 1998. Modern food microbiology. 5th ed. GAITHERSBURG, MD, USA : Aspen Publishers, 790 p. ISBN: 978-1-4899-4407-8.

Rahman, S. M. E., Ding, T., Oh, D. H. 2010. Inactivation effect of newly developed low concentration electrolyzed water and other sanitizers against microorganisms on spinach. Food control, vol. 21, no. 10, p. 1383-1387. https://doi.org/10.1016/j.foodcont.2010.03.011

Schneider, K. R., De, J., Li, Y., Sreedharan, A., Goodrich Schneider, R., Danyluk, M. D., Pahl, D. M., Walsh, C. S., Todd-Searle, J., Schaffner, D. W., Kline, W., Buchanan, R. L. 2017. Microbial evaluation of pre- and post-processed tomatoes from Florida, New Jersey and Maryland packinghouses. Food control, vol 73, p. 511-517. https://doi.org/10.1016/j.foodcont.2016.08.048

Shi, X., Wu, Z., Namvar, A., Kostrzynska, M., Dunfield, K., Warriner, K. 2009. Microbial population profiles of the microflora associated with pre- and postharvest tomatoes contaminated with Salmonella Typhimurium or Salmonella Montevideo. Journal of applied microbiology, vol. 107, no. 1, p. 329-338. https://doi.org/10.1111/j.1365-2672.2009.04211.x

Tokarskyy, O., De, J., Fatica, M. K., Brecht, J., Schneider, K. R. 2018. Survival of Escherichia coli O157:H7 and Salmonella on bruised and unbruised tomatoes from three ripeness stages at two temperatures. Journal of food protection, vol. 81, no. 12, p. 2028-2034. https://doi.org/10.4315/0362-028X.JFP-18-220

Tokarskyy, O., Schneider, K. R. 2019. Influence of temperature, humidity, and diluent type on survival of Salmonella spp. on the surface of raw tomatoes. Potravinarstvo Slovak journal of food sciences, vol.13, no 1., p. 325-330. https://doi.org/10.5219/1121

Tokarskyy, O., Marshall, D. L. 2010. Novell technologies for microbial spoilage prevention. In: Toldra, F. Handbook of meat processing. Hoboken, NJ : Wiley-Blackwell Publishing, p. 263-286. ISBN 978-0-813-82182-5. https://doi.org/10.1002/9780813820897.ch14

Tokarskyy, O., Schneider, K. R., Berry, A., Sargent, S. A., Sreedharan, A. 2015. Sanitizer applicability in a laboratory model strawberry hydrocooling system. Postharvest biology and technology, vol. 101, p. 103-106. https://doi.org/10.1016/j.postharvbio.2014.12.004



How to Cite

Tokarskyy, O., & Korda, M. (2019). Microbiological comparison of visibly dirty and visibly clean mature green tomatoes before and after treatments with deionized water or chlorine in model overhead spray brush roller system. Potravinarstvo Slovak Journal of Food Sciences, 13(1), 779–783. https://doi.org/10.5219/1178