USO DE EXTRATOS VEGETAIS PARA HIGIENIZAÇÃO DE ALFACE

Abstract

Every day, more and more people, by lifestyle choice or by medical or nutritionist recommendation, are consuming more raw salads, among which, lettuce stands out as the best known and most consumed leafy vegetable in Brazil. However, concern regarding human health prejudice by raw salads has increased. The population concerning about food safety results in new sanitation techniques development to eliminate or reduce contamination by microorganisms in salads is proportionally to their consumption. This paper aimed to evaluate the antimicrobial activity in the medicinal plants, camomile (Matricaria chamomilla), mauve (Malva sylvestris L.), clove (Syzygium aromaticum), and lemon clove (Citrus limonia Osbeck), compared to traditional treatments with natural water and bleach solution (sodium hypochlorite - NaClO). Aqueous extracts of these medicinal plants were obtained by macerating 5 g of the plant material, adding 500 mL of distilled water, keeping it for three days, and it was shaken twice a day in this period. At the end of this period, the extract was filtered and frozen to make microbiological and physicochemical tests. The extract concentration was empirically stipulated at 1%. The assay was carried out in triplicate among the solutions used. Aqueous extracts of clove, chamomile, mauve, and clove lemon were diluted successively in the ratio of 1:1 in buffer solution, and then obtained the dilutions (1/2, 1/4, 1/8, 1/16, 1/32, 1/64, 1/128, 1/256, 1/512). Lettuces were washed and prepared following popular knowledge for initial standardization of the experiments. After that, the vegetables were inoculated with the bacteria Escherichia coli, Salmonella aureus, and Salmonella sp. at the concentration of 107 CFU mL-1

, left to rest for one hour and then submitted to the treatments. Considering the results, an antimicrobial activity of clove aqueous extract was found up to dilution 1/4, according to the methodology used, 400 AU mL-1

for the tested strains of E. coli, 100 AU mL-1 for

Salmonella sp. and 400 AU mL-1

for S. aureus. In addition, when clove extract was

tested on lettuce leaves, there was a decrease in the number of CFU mL-1

in the three strains tested in relation to the negative control. The extracts of mauve, clove lemon, and camomile did not show significant results regarding the contaminants reduction.