Antimicrobial Potential of Cauliflower, Broccoli, and Okara Byproducts Against Foodborne Bacteria

Abstract

The antimicrobial potential of cauliflower, broccoli, and okara byproducts was assessed against Gram-positive and Gram-negative bacteria. Salmonella enterica serovar Typhimurium, Escherichia coli O157:H7, Bacillus cereus, and Listeria monocytogenes serovar 4b growth behavior was assessed under exposure to 5% vegetable byproducts added to the reference medium, buffered peptone water (0.1% [wt/vol]), at 37°C. Although the byproducts were not effective against L. monocytogenes, they were bactericidal against Salmonella Typhimurium, E. coli O157:H7, and B. cereus. The most promising results were achieved with the cauliflower-Salmonella Typhimurium combination, because the bacterial population was reduced by 3.11 log10 cycles after 10 h of incubation at 37°C as a result of 5% cauliflower addition. Further studies were carried out for this combination, at different cauliflower concentrations (0, 0.5, 1, 5, 10, and 15%) and at temperatures in the range of 5-37°C. The greatest inactivation level (6.11 log10 cycles) was achieved at refrigeration temperature (5°C) using 15% cauliflower addition. Both temperature and cauliflower concentration significantly (p≤0.05) influenced the Salmonella Typhimurium inactivation level. The kinetic parameters were adjusted to mathematical models. The modified Gompertz mathematical model provided an accurate fit (root-mean-square error (RMSE) [0.00009-0.21] and adjusted-R(2) [0.81-0.99]) to experimental Salmonella Typhimurium survival curves describing inactivation kinetics of the pathogen to the antimicrobial effect of cauliflower byproduct.

In vivo Antimicrobial Activity Assessment of a Cauliflower By-Product Extract Against Salmonella Typhimurium

“…It has been reported that the lifespan of C. elegans is related with genetic and environmental factors, such as temperature, food availability and composition (Blumenthal and Steward, 1997;Uno and Nishida, 2016). According to Sanz-Puig et al (2015a) and Vieira (2013), cauliflower by-product infusion provides bioactive compounds such as polyphenols. It has been found that polyphenols contained in hydrophilic extracts of Brassica species are responsible for 80-95% of their total antioxidant capacity (Kurilich et al, 2002;Xianli et al, 2004).…”

“…Some natural antimicrobials by-products from plants (essential oils and plant extracts) have demonstrated their effectiveness against Salmonella Typhimurium in vitro (Sanz-Puig et al, 2015a;Mohamed et al, 2016). It has also been found that many vegetables in the Cruciferae family have antimicrobial properties against several microorganisms of clinical importance.…”

S. Typhimurium virulence changes caused by exposure to different non-thermal preservation treatments using C. elegans

“…The next step was to evaluate virulence shifts in S. Typhimurium resulting from repetitive exposure to cauliflower by-product infusion. Cauliflower byproduct infusion contained bioactive compounds, as a ascorbic acid, carotenoids, flavonoids and, mainly, polyphenols such as galic acid, quercetin or rutin (Sanz-Puig et al, 2015;Vieira, 2013). To accomplish this goal, C. elegans were fed with S. Typhimurium exposed once and three times to cauliflower by-product infusion during their entire lifespan, and subsequently compared with C. elegans fed with untreated S. Typhimurium (control group).…”

Persistence of Indicator and Pathogenic Microorganisms in Broccoli following Manure Spreading and Irrigation with Fecally Contaminated Water: Field Experiment

“…Many factors can affect bacterial survival on fruits and vegetables at the preharvest stage, including UV exposure (47,62), temperature (25), and produce surface drying (62). It is also known that produce may contain essential oils, antioxidants, and antimicrobial components that have an impact on microorganisms (59). Such compounds are naturally present in broccoli, and they may explain the low E. coli prevalence observed in this study.…”