Electrolytic treatment and biosurfactants applied to the conservation of Eugenia uniflora fruit

Abstract

Microorganisms are the primary responsible for food poisoning and food spoilage. The purpose of this study was to evaluate different fruit washing methods with tap water, electrolyzed water and rhamnolipids solution produced by Pseudomonas aeruginosa LBI, in order to inhibit microbial growth. The tested organism was Eugenia uniflora. The fruits were washed and periodically inoculated into culture media to evaluate and count the colonies on the fruit surface. It was also observed the deterioration level of the fruits after each treatment. The results showed that treatment with rhamnolipids were the most efficient, inhibiting the growth of fungi and bacteria. The electrolyzed water proved to be very efficient in bacterial inhibition at the initial time, but in the final time it did not present any inhibitory effect. The electrolyzed water was also not effective in eliminating fungus. Washing with tap water was the less efficient treatment of all. The only treatment that showed an increased durability has been with rhamnolipids, increasing shelf life by up to two days. Thus rhamnolipids are the most recommended method for fruits sanitation.

Application of surface-active substances produced by Nocardia vaccinii ІМВ В-7405 for the treatment of vegetables

“…In the studies of the influence of microbial SAS on the extension of the storage time of fruit-and-vegetables products high enough concentration of preparations, 1 -3 g/L, were used [2,8,[18][19][20][21]. Our previous studies showed that SAS synthesized by N.vacсinii ІМV В-7405 had high antimicrobial activities [16] [23].…”

“…Vegetables of the first group were not treated at all, vegetables of the second group were washed with tap water, and vegetables of the third group were washed with the solutions of SAS with concentrations of 0.25 or 0.5 g/L. Vegetables were placed in the glass cylinder, 250 mL of tap water or the SAS solution was added, treatment lasted for 5 min, and after that vegetables were taken off and placed on the plates at the room temperature for observation [8]. Microbiological analysis was done before the beginning of the vegetables storage.…”

“…However, the total post-harvest losses were assessed as 800-964 thousand tons in 2017 [4], which consist about US$30-37 million. To extend shelf life of vegetables they can be treated using physical methods such as hot-water immersion, low temperature storage, modified atmosphere packaging technology, the treatment with gamma radiation or by pulsed electric field and chemical methods such as application of acidifying agents, chemical reductants, inhibitors of enzymes activities, sequestrants [5][6][7][8]. The treatment of the vegetables using physical methods can cause their mechanical damages such as bruises, abrasions and cuts which make them more sensitive to desiccation and shriveling, increase in respiration rate and ethylene emission, speed up the wilting and enzymatic browning.…”

“…The treatment of the vegetables using physical methods can cause their mechanical damages such as bruises, abrasions and cuts which make them more sensitive to desiccation and shriveling, increase in respiration rate and ethylene emission, speed up the wilting and enzymatic browning. The high temperatures can cause yellow discoloration of green vegetables, and the use of modified atmosphere packing stipulates determination of optimal gas composition for every certain product [8]. Application of the physical methods for vegetables treatment also requires special equipment.…”

Evaluating the potential of electrolysed water for the disinfection of citrus fruit in packinghouses

“…The electrodes were connected to a source of direct current Dawer‐FCC‐3005D (DAWER do Brasil Ltda. ‐ Sao Paulo, Brazil) and attached to a magnetic stirrer to keep the resulting EW as homogenous as possible, according to the previous procedure described by Dilarri et al 14 . The electrolysis time ranged from 5 to 9 min at a constant current (1 A).…”