The Evaluation of Antibacterial Activity of Copper Sheets in the Germination of Alfalfa Seeds (<em>Medicago sativa</em> L.) within a Rotating Drum



  • José F. Reyes Faculty of Agricultural Engineering, Universidad de Concepción, Chile
  • Johannes P.F. de Bruijn Faculty of Agricultural Engineering, Universidad de Concepción, Chile
  • Guillermo F. Tolosa Faculty of Agricultural Engineering, Universidad de Concepción, Chile
  • Pedro M. Aqueveque Faculty of Agricultural Engineering, Universidad de Concepción, Chile
  • Christian L. Correa Faculty of Agricultural Engineering, Universidad de Concepción, Chile



Sprouts, alfalfa, Escherichia coli, copper, food safety


— The consumption of sprouts in the human diet has grown during the last years, but great concern raised from public health institutions, food industry and consumers regarding their safety since foodborne diseases caused by microorganisms have been reported. Copper metal as a contact surface was studied during the germination of alfalfa seeds (Medicago sativa L.) inside a rotating drum on a laboratory scale and compared with a plastic surface of food-grade. A system of three rotating drums was used inside a thermo-regulated chamber to germinate seeds. To evaluate the antibacterial activity of copper sheets, alfalfa seeds were inoculated with 4.2 log cfu g-1 of Escherichia coli and after 84 hours of germination sprouts were evaluated for E. coli, mesophilic aerobic bacteria, the content of copper and other minerals (potassium, calcium, magnesium, sodium, iron, manganese, and zinc), total mass, unit mass and length, and color. The contact of alfalfa sprouts with copper sheets allowed to reduce the E. coli load from 6.54 to <0.1 log cfu g-1. However, all sprouts exceeded in copper (> 10 ppm) according to Food Sanitary Regulations. Germinated mass and length decreased after copper treatments. No statistically significant differences were observed between treatments for the remaining quality parameters. Finally, it is concluded that copper was very efficient in reducing the microbial load of E. coli in alfalfa sprouts, complying with the regulations established by the Chilean Ministry of Health.


Abadias, M., Usall, J., Anguera, M., Solsona, C., & Viñas, I., “Microbiological quality of fresh, minimally-processed fruit and vegetables, and sprouts from retail establishments”, Int. J. Food Microbiol., 123(1-2), 121-129, 2008.

Yang, Y., Meier, F., Ann Lo, J., Yuan, W., Lee Pei Sze, V., Chung, H.J., & Yuk, H.G., “Overview of recent events in the microbiological safety of sprouts and new intervention technologies”, Compr. Rev. Food Sci. Food Saf., 12(3), 265-280, 2013.

Beuchat, L.R., Ward, T.E., & Pettigrew, C.A., “Comparison of chlorine and prototype produce wash product for effectiveness in killing Salmonella and Echerichia coli O157:H7 on alfalfa seeds”, J. Food Prot., 64(2), 152-158, 2001.

Keshri, J., Krouptiski, Y., Abu-Fani, L., Achmon, Y., Stern Bauer, T., Zarka, O., Maler, I., Pinto, R., Sela Saldinger, S., “Dynamics of bacterial communities in alfalfa and mung bean sprouts during refrigerated conditions”, Food Microbiol., 84,103261, 2019.

Charkowski, A.O., Barak, J.D., Sarreal, C.Z., & Mandrell, R.E., “Differences in growth of Salmonella enterica and Escherichia coli O157:H7 on alfalfa sprouts”, Appl. Environ. Microbiol., 68(6), 3114–3120, 2002.

Putnam, D.H., Summers, C.G., & Orloff, S.B., “Alfalfa production systems in California”, University of California Alfalfa & Forages, University of Davis, USA, 2007.

Colmenares de Ruiz, A.S., & Bressani, R., “Effect of germination on the chemical composition and nutritive value of amaranth grain”, Cereal Chem., 67(6), 519-522, 1990.

Undersander, D., Hall, M.H., Vassalotti, P., & Cosgrove, D., “Alfalfa germination & growth”, National Alfalfa & Forage Alliance. St. Paul, USA, 2011.

Khan, I., Tango, C.N., Miskeen, S., Lee, B.H., & Oh, D.H., “Hurdle technology: A novel approach for enhanced food quality and safety – A review”, Food Control, 73(B), 1426-1444, 2017.

Neetoo, H., Mu Ye, Chen, H., “Potential application of high hydrostatic pressure to eliminate Escherichia coli O157:H7 on alfalfa sprouted seeds”, Int. J. Food Microbiol., 128, 348-353, 2008.

Peñas, E., Gómez, R., Frías, J., Vidal-Valverde, C., “Efficacy of combinations of high pressure treatment, temperature and antimicrobial compounds to improve the microbiological quality of alfalfa seeds for sprout production”, Food Control. 20, 31–39, 2009.

Millan-Sango, D., Sammut, E., Van Impe, J.F., Valdramidis, V.P., “Decontamination of alfalfa and mung bean sprouts by ultrasound andaqueous chlorine dioxide”, LWT Food Sci. Technol., 78, 90-96, 2017.

Singh, N., Singh, R.K., Bhunia, A.K., “Sequential disinfection of Escherichia coli O157:H7 inoculated alfalfa seeds before and during sprouting using aqueous chlorine dioxide, ozonated water, and thyme essential oil”, Lebensm. Wiss. Technol., 36, 235–243, 2003.

Baker, K.A., Beecher, L., Northcutt J.K., “Effect of irrigation water source and post-harvest washing treatment on the microflora of alfalfa and mung bean sprouts”, Food Control, 100, 151–157, 2019.

Mohammad, Z., Kalbasi-Ashtari, A., Riskowski, G., Castillo, A., “Reduction of Salmonella and Shiga toxin-producing Escherichia coli on alfalfa seeds and sprouts using an ozone generating system”, Int. J. Food Microbiol., 289, 57-63, 2019.

Wilks, S.A., Michels, H., & Keevil, C.W., “The survival of Escherichia coli O157 on a range of metal surfaces”, Int. J. Food Microbiol., 105(3), 445-454, 2005.

Noyce, J.O., Michels, H., & Keevil, C.W., “Use of copper cast alloys to control Escherichia coli O157 cross-contamination during food processing“, Appl. Environ. Microbiol., 72(6), 4239-4244, 2006.

Wilks, S.A., Michels, H.T., & Keevil, C.W., “Survival of Listeria monocytogenes Scott A on metal surfaces: implications for cross-contamination”, Int. J. Food Microbiol., 111(2), 93-98, 2006.

Grass, G., Rensing, C., & Solioz, M., “Metallic copper as an antimicrobial surface”, Appl. Environ. Microbiol., 77(5), 1541-1547, 2011.

Warnes, S.L., Caves, V., & Keevil, C.W., “Mechanism of copper surface toxicity in Escherichia coli O157:H7 and Salmonella involves immediate membrane depolarization followed by slower rate of DNA destruction which differs from that observed for Gram-positive bacteria”, Environ. Microbiol., 14(7), 1730-1743, 2012.

Santo, C., Taudte, N., Nies, D.H., & Grass, G., “Contribution of copper ion resistance to survival of Escherichia coli on metallic copper surfaces”, Appl. Environ. Microbiol., 74(4), 977-986, 2008.

Santo, C., Lam, E.W., Elowsky, C.G., Quaranta, D., Domaille, D.W., Chang, C.J. & Grass, G., “Bacterial killing by dry metallic copper surfaces”, Appl. Environ. Microbiol., 77(3), 794-802, 2011.

Nyenhuis, J., & Drelich, J.W., “Essential micronutrient biofortification of sprouts grown on mineral fortified fiber mats”, International Journal of Biological, Biomolecular, Agricultural, Food and Biotechnological Engineering, 9(9), 943-946, 2015.

Fernandes, J.C., & Henriques, F.S., “Biochemical, physiological, and structural effects of excess copper in plants”, Bot. Rev., 57(3), 246-273, 1991.

Ahsan, N., Lee, D.G., Lee, S.H., Kang, K.Y., Lee, J.J., Kim, P.J., Yoon, H.S., J.-S. Kim, J.S., & Lee B.H., “Excess copper induced physiological and proteomic changes in germinating rice seeds”, Chemosphere, 67(6), 1182-1193, 2007.

Lamichhane, J.R., Osdaghi, E., Behlau, F., Köhl, J., Jones, J.B., & Aubertot, J.N., “Thirteen decades of anti-microbial copper compounds applied in agriculture. A review”, Agron. Sustain. Dev., 38: 28, 2018.

Peralta, J.R., Gardea-Torresdey J.L., Tiemann, K.J., Gomez, E., Arteaga, S., Rascon, E., & Parsons, J.G., “Uptake and effects of five heavy metals on seed germination and plant growth in alfalfa (Medicago sativa L.)”, Bull. Environ. Contam. Toxicol., 66(6), 727-734, 2001.

Boroş, M.N., & Micle, V., “Effects of copper-induced stress on seed germination of maize (Zea Mays L.)”, Agricultura, 3-4(95-96), 17-23, 2015.

Fu, T.J., Reineke, K.F., Chirtel, S., & VanPelt, O.M., “Factors influencing the growth of Salmonella during sprouting of naturally contaminated alfalfa seeds”, J. Food Prot., 71(5), 888-896, 2008.

Fu, T.J., Stewart, D., Reineke, K., Ulaszek, J., Schlesser, J. M. Tortorello, M., “Use of spent irrigation water for microbiological analysis of alfalfa sprouts”, J. Food Prot., 64(6), 802-806, 2001.

Sadzawka, A., Carrasco, M.A., Demanet, R., Flores, H., Grez, R., Mora, M.L. & Neaman, A., “Métodos de análisis de tejidos vegetales”, (2a. ed.). Serie Actas INIA Nº40. INIA La Platina. Santiago, Chile, 2007.

Plaza, L., de Ancos, B., & Cano, M.P., “Nutritional and health-related compounds in sprouts and seeds of soybean (Glycine max), wheat (Triticum aestivum L.) and alfalfa (Medicago sativa) treated by new drying method”, Eur. Food Res. Technol., 216(2), 138-144, 2003.

MINSAL (Chile), “Reglamento Sanitario de los Alimentos”, DTO. No. 977/96. Ministerio de Salud. Santiago, Chile, 1997.

Singh, D., Nath, K. & Sharma, Y.K., “Response of wheat seed germination and seedling growth under copper stress”, J. Environ. Biol., 28(2), 409-414, 2007.




How to Cite

Reyes, J. F., de Bruijn, J. P. ., Tolosa, G. F., Aqueveque, P. M., & Correa, C. L. (2020). The Evaluation of Antibacterial Activity of Copper Sheets in the Germination of Alfalfa Seeds (<em>Medicago sativa</em> L.) within a Rotating Drum: None. Asian Journal of Agriculture and Food Sciences, 8(4).