Adhesion capacity and biofilm formation of Escherichia coli and Salmonella in tomato (Solanum lycopersicum L.) in postharvest stage

ISHS Secretariat
Adhesion capacity and biofilm formation of Escherichia coli and Salmonella in tomato (Solanum lycopersicum L.) in postharvest stage

Itzel Rojas Puebla is a doctoral student in the Faculty of Agricultural Sciences at Autonomous University of the State of Mexico. Her research focused on evaluating bacterial strains from different pathotypes and origins to develop biofilm using the epidermis of tomato fruit (Solanum lycopersicum L.) as a substrate. The presence of bacteria like E. coli O157:H7 and Salmonella in food is a warning of an outbreak of disease. E. coli O157:H7 can colonize edible plants by means of adhesion, survival, and internalization. This bacterium can potentially produce biofilm without causing virulence to humans. The objective of this research was to evaluate the capacity of adhesion and biofilm formation of E. coli and Salmonella on tomato fruits during the postharvest stage. We considered four bacterial serotypes and used the plate microdilution technique. We determined cfu mL-1 and physicochemical variables including weight, pH, titratable acidity, and total soluble solids. The results showed significant differences among the four serotypes and time (13 days). Average optical density (OP) for the treatment was: Control (0.78 nm), 49766 (1.51 nm), DL933 (1.47 nm), HB101 (1.42 nm). The best formation occurred about 4 to 5 days after inoculation (DAI). This is consistent with the highest counts of CFU 4 and 6 DAI, with an average of 3.65Log10. The results confirm that pathogens like E.coli can adhere to fruits, developing a biofilm, which could turn into a potential threat to food safety and could be a source of infectious disease. The methods used to guarantee food safety are based on adopting good agricultural practices (GAP), good food handling practices (GFHP) and a hazard analysis and control of critical points (HACCP).

Itzel Rojas Puebla won the ISHS Young Minds Award for the best oral presentation at the V International Conference on Postharvest and Quality Management of Horticultural Products of Interest for Tropical Regions, which was held virtually in Mexico in October 2021.

Itzel Rojas Puebla, Facultad de Ciencias Agricolas, Universidad Autónoma del Estado de México, El Cerrillo Piedras Blancas, C.P. 50295, Toluca de Lerdo, Estado de México, Mexico, e-mail:

The article is available in Chronica Horticulturae

Escherichia coli
Solanum lycopersicum L.
Young Minds Award Winners