Effectiveness of green tea extract on the native microflora of ready-to-eat beetroot: evaluation of different application methods.

MARTÍNEZ MELO, LUCILA; FINTEN GABRIEL; JAGUS ROSA JUANA; MARTÍNEZ MELO, LUCILA; FERNANDEZ, MARÍA VERÓNICA; JAGUS ROSA JUANA; AGÜERO MARÍA VICTORIA; FERNANDEZ, MARÍA VERÓNICA; AGÜERO MARÍA VICTORIA; FINTEN GABRIEL

ACTA HORTICULTURAE

International Society of Horticultural Science

Lugar: Bruselas; Año: 2018 vol. 1194 p. 895 - 902

0567-7572

The effectiveness of green tea extracts against the native microflora of beetroot and the impact of the application methodology on its antimicrobial efficiency were evaluated. Beetroots were washed, peeled, disinfected with 200 ppm sodium hypochlorite and grated. Solutions of green tea at 0.43, 0.85 and 1.70% were applied by two different methodologies: spraying (TS1, TS2 and TS3, respectively) and dipping (TD1, TD2 and TD3, respectively), with the same volume of retained solution in all cases. Control samples were treated with sterile distilled water (CS and CD). Samples were packaged in 10 g-units (PD960, Cryovac, Argentina) and stored at 15°C for 96 h. Aerobic mesophilic bacteria (AMB) and yeasts and molds (Y&M) were evaluated. Initial counts were 4.4±0.4 and 3.1±0.2 log CFU g-1, respectively. Control samples, regardless the application method, presented a continuous AMB and Y&M growth, reaching values of 9.4±0.4 and 6.3±0.3 log CFU g-1, respectively, at 96 h. Spraying methodology did not result efficient as TS1-TS3 samples presented AMB and Y&M behavior similar to the control. Dipping methodology led to initial reductions of 1.2-1.8 log cycle for AMB, depending on tea concentration; and 1 log for Y&M, regardless of concentration. After that, TD1 and TD2 samples showed significant AMB and Y&M regrowths, reaching counts similar to CD at 96 h, while TD3 counts continued declining until undetectable levels during the first 24h followed by a slight regrowth, reaching AMB and Y&M counts 3.8 and 1.2 lower than CD at 96 h. Differences found between application methodologies could be associated with the high surface:volume ratio of grated beetroot, being the dipping more efficient than spraying to achieve complete contact between antimicrobials and product surface. This work allowed us to select the tea extract concentration that effectively controls the development of beetroot microflora as well as the application methodology.