Correlation between Time of Harvesting and Duration before Cooling on the Microbial Quality of French Bean (Phaseolus vulgaris L.)

Author(s): E. O. Ogumo, C. N. Kunyanga, M. W. Okoth, J. W. Kimenju

French bean is a major export crop from Kenya into United Kingdom and Europe. It is usually consumed cooked. Food safety is one of the most important factors that influence success of fresh produce export. Microbial contamination is one of the food safety concerns in fresh produce industry. This study focused on understanding the correlation between harvesting time and duration before cooling on the microbial quality of French beans. To assess the microbial quality of French beans, samples of French beans were harvested at different times of the day, 7am, 9am, 11am , 1pm and 3pm. The harvested beans were then held in the produce shed before start of cooling for various durations; 0 hour, 2 hours, 4 hours, 6 hours and 8 hours. The samples were later graded and packed in modified atmosphere packaging (MAP) bags. The samples were analyzed following standard plate technique to determine the microbial qualities of French bean samples. Total viable counts (TVC) in these samples showed mean values ranging from 0.7 to 3.3×105 CFUs g-1 for total Enterobacteriacea, Listeria monocytogenes, moulds and Staphylococcus aureus. Of the microorganisms isolated, Enterobacteriacea (71.6%) was the highest, followed by Staphylococcus aureus (20.9%), Moulds (7.2%) and Listeria monocytogenes at 0.3%. The harvesting time and duration before cooling had significant effect on population of microorganisms with those harvested early in the morning having the highest population. The high presence of microbial load in samples harvested early morning can be attributed to poor personal hygiene of the food handlers and excessive leaf wetness in the morning. There is need to do further research on the effect of solar radiation on the growth and survival of Listeria monocytogenes, it was evident that the Listeria population decreased significantly with every delay in harvesting, which could also be attributed to dry leaf and pod surfaces. French bean contamination in the field may result from various sources, ranging from soil, irrigation water, contaminated harvesting tools and equipment and contamination from harvesters and food handlers. It is therefore important to know the possible sources of contamination and put in place measure to eliminate or reduce contamination. Hygiene practices like hand washing after using the toilet, before handling produce and avoiding touching of face, skin and nose can be useful in reducing contamination from food handlers. Use of gloves to protect hands during harvesting is necessary to reduce contamination.

Harvesting time, Duration before cooling, Phaseolus vulgaris L., Microbial quality, Totall Viable Count, Enterobacteriaceae, Listeria monocytogenes, Staphylococcus aureus, Food Safety, Hazard Analysis Critical Control Points (HACCP)

1. Acevedo, L., Mendoza, C., Oyón, R. 2001. Total and fecal coliforms, some Enterobacteriaceae, Staphylococcus sp. and moulds in salads for hot dogs sold in Maracay, Venezuela]. Arch Latinoam Nutrition 2001;51:366-70. (Spanish). - http://dx.doi.org/10.1002/stab.200101300
2. Anonymous, 1987. Microbiology of food and animal feeding stuffs Enumeration of yeasts and mold. ISO 7954:1987, International Organization for Standardization, Geneva, Switzerland, - http://dx.doi.org/10.3403/bsiso21527
3. Arumugaswamy, R. K. G., Rahamat, R. A. G., Nadzriah B. A. H. S. (1994). Prevalence of Listeria monocytogenes in foods in Malaysia. International Journal of Food Microbiology, 23: 117-121. - http://dx.doi.org/10.1016/0168-1605(94)90227-5
4. Aycicek H, Oguz U, Karci K. (2006). Determination of total aerobic and indicator bacteria on some raw eaten vegetables from wholesalers in Ankara, Turkey. International Journal of Hygiene and Environmental Health, 209:197-201. - http://dx.doi.org/10.1016/j.ijheh.2005.07.006
5. Badosa, E., Trias, R., Parés, D., Pla, M., Montesinos, E. (2008). Microbiological quality of fresh fruit and vegetable products in Catalonia, Spain using normalized plate counting methods and real time polymerase chain reaction (QPCR). Journal of the Science of Food and Agriculture, 88:605-11. - http://dx.doi.org/10.1002/jsfa.3124
6. Barth, M., Hankinson, T. R., Zhuang, H., Breidt, F. (2009). Microbiological spoilage of fruits and vegetables. In Compendium of the microbiological spoilage of foods and beverages (pp. 135-183). Springer, New York, NY. - http://dx.doi.org/10.1007/978-1-4419-0826-1_6
7. Breer, C., Baumgartner, A. 1992. Occurence and behavior of Listeria monocytogenes in salads, vegetables, and fresh vegetables juice. Arch. Lebensmittelhyg, 43: 108-110. - http://dx.doi.org/10.5897/ajfs2013.1036
8. Büyükünal, S. K., Issa, G., Aksu, F., Vural, A. (2015). Microbiological quality of fresh vegetables and fruits collected from supermarkets in Istanbul, Turkey. - http://dx.doi.org/10.11648/j.jfns.20150304.13
9. De Simon, M., Tarrago, C., Ferrer, M. D. 1992. Incidence of Listeria monocytogenes in fresh foods in Barcelona (Spain). International Journal of Food Microbiology., 16: 153-156. - http://dx.doi.org/10.1016/0168-1605(92)90008-q
10. Directorate, C. (2002). Risk profile on the microbiological contamination of fruits and vegetables eaten raw. Abadias M, Usall J, Anguera A, Solsona C, Vinas I (2008). Microbiological quality of fresh, minimally-processed fruit and vegetables, and sprouts from retail establishments. International Journal of Food Microbiology, 123, 121–129. - http://dx.doi.org/10.1016/j.ijfoodmicro.2007.12.013
11. Eni, A. O., Oluwawemitan, I. A., Solomon, O. U. (2010). Microbial quality of fruits and vegetables sold in Sango Ota, Nigeria. African Journal of Food Science, 4(5): 291-296. - http://dx.doi.org/10.4314/tzool.v7i1.52073
12. Jeddi, M. Z., Yunesian, M., Gorji, M. E. H., Noori, N., Pourmand, M. R., Khaniki, G. R. J. (2014). Microbial evaluation of fresh, minimally-processed vegetables and bagged sprouts from chain supermarkets. Journal of Health, Population, and Nutrition, 32(3): 391-399 - http://dx.doi.org/10.1201/9781420031850.ch13
13. Kader A. 2002. Chapter 2: quality parameters of fresh-cut fruit and vegetable products. In: Lamikanra O, editor. Fresh-cut fruits and vegetables-science, technology and market. Boca Raton, Fla.: CRC Press. p 11–20. - http://dx.doi.org/10.1201/9781420031874.ch2
14. Kasim, R., Kasim, M. U. (2015). Biochemical changes and color properties of fresh-cut green bean (Phaseolus vulgaris L. cv. gina) treated with calcium chloride during storage. Food Science and Technology, 35(2): 266-272. - http://dx.doi.org/10.1590/1678-457x.6523
15. Likotrafiti, E., Smirniotis, P., Nastou, A., Rhoades, J. (2013). Effect of relative humidity and storage temperature on the behavior of Listeria monocytogenes on fresh vegetables. Journal of Food Safety, 33(4): 545-551 - http://dx.doi.org/10.1111/jfs.12087
16. Luo, Y., He, Q., McEvoy, J. L. (2010). Effect of storage temperature and duration on the behavior of Escherichia coli O157: H7 on packaged fresh‐cut salad containing romaine and iceberg lettuce. Journal of Food Science, 75(7): M390-M397. - http://dx.doi.org/10.1111/j.1750-3841.2010.01722.x
17. Miedes, E and Lorences, E.P (2004). Apple and tomato fruits cell-wall hemicelluloses and xyloglucan degradation during Penicillium expansum infection. Journal of Agricultural and Food chemistry. 52: 7957-7963 - http://dx.doi.org/10.1021/jf048890f
18. Onuorah, S. C., Udemezue, O. I., Uche, J. C., Okoli, I. C. 2013. Fungi Associated with the Spoilage of Pineapple Fruits in Eke Awka Market Anambra State. The Bioscientist. 1(1):22-27 - http://dx.doi.org/10.21859/ajlsr-040301
19. Qadri, O. S., Yousuf, B., Srivastava, A. K. (2015). Fresh-cut fruits and vegetables: Critical factors influencing microbiology and novel approaches to prevent microbial risks—A review. Cogent Food & Agriculture, 1(1),:1121606. - http://dx.doi.org/10.1080/23311932.2015.1121606
20. Uzeh RE, Alade FA, Bankole M (2009). The microbial quality of prepacked mixed vegetable salad in some retail outlets in Lagos, Nigeria. African Journal of Food Science. 3 (9): 270-272. - http://dx.doi.org/10.5539/jfr.v2n6p48