Chemical antibacterials are widely used to control microbial growth but have raised concerns about health risks. It is necessary to find alternative, non-toxic antibacterial agents for the inhibition of pathogens in foods or food contact surfaces. To develop a non-toxic and “green” food-grade alternative to chemical sanitizers, we formulated a multicomponent antibacterial mixture containing Rosmarinus officinalis L., Camellia sinensis L., citric acid, and ε-polylysine and evaluated its bactericidal efficacy against Staphylococcus aureus, Escherichia coli, Bacillus cereus, Salmonella Enteritidis, and Listeria monocytogenes on food contact surfaces. A combination of the agents allowed their use at levels lower than were effective when tested individually. At a concentration of 0.25%, the multicomponent mixture reduced viable cell count by more than 5 log CFU/area, with complete inactivation 24 h after treatment. The inhibitory efficacy of the chemical antibacterial agent (sodium hypochlorite, 200 ppm) and the multicomponent antibacterial mixture (0.25%) on utensil surfaces against S. aureus, E. coli, S. Enteritidis, and L. monocytogenes were similar, but the multicomponent system was more effective against B. cereus than sodium hypochlorite, with an immediate 99.999% reduction on knife and plastic basket surfaces, respectively, and within 2 h on cutting board surfaces after treatment. A combination of these food-grade antibacterials could be a useful strategy for inhibition of bacteria on food contact surfaces while allowing use of lower concentrations of its components than are effective individually. This multicomponent food-grade antibacterial mixture may be a suitable “green” alternative to chemical sanitizers.

The prevalence and characteristics of low-temperature-tolerant Bacillus cereus (psychrotolerant B. cereus) in green leaf lettuce collected during cold chain were investigated. Among the 101 isolated B. cereus samples, only 18 were capable of growth at 7 °C, and these isolates shared potential health hazard characteristics with mesophilic isolates. Most psychrotolerant B. cereus isolates contained various combinations of nheA, nheB, nheC, hblA, hblA, hblC, hblD, cytK, and entFM. Most isolates of psychrotolerant B. cereus possessed at least two enterotoxin genes and 28% of isolates harbored tested nine enterotoxin genes. Additionally, the psychrotolerant B. cereus isolates showed resistance to tetracycline and rifampin and intermediate levels of resistance to clindamycin. A total of 23% of isolates among psychrotolerant B. cereus displayed a high level of biofilm formation at 7 °C than at 10 °C or 30 °C. The results of this study indicate that cold distribution and storage for green leaf lettuce may fail to maintain food safety due to the presence of enterotoxigenic, antibiotic-resistant, and strong biofilm forming psychrotolerant B. cereus isolates, which therefore poses a potential health risk to the consumer. Our findings provide the first account of the prevalence and characteristics of psychrotolerant B. cereus isolated from green leaf lettuce during cold storage, suggesting a potential hazard of psychrotolerant B. cereus isolates to public health and the food industry.

Chromanols from marine algae are studied for drug development due to its prominent bioactive properties, and mojabanchromanol (MC), a chromanol isolated from a brown algae Sargassum horneri, is found to possess anti-oxidant potential. In this study, we hypothesized MC may attenuate particulate matter (PM)-induced and reactive oxygen species (ROS)-mediated inflammatory responses in airways and tried to identify its potential and underlying mechanism against PM (majority <2.5 µm in diameter)-induced inflammatory responses in a lung type II alveolar epithelial cell line, MLE-12. MC attenuated PM-induced malondialdehyde (MDA), a lipid peroxidation end product, and 8-hydroxydeoxyguanosine (8-OHdG), the most representative DNA oxidative damage product, further validating MC’s potential in attenuating PM-induced oxidative stress. MC also suppressed PM-triggered TLR2/4/7 activation in MLE-12 cells. Moreover, MC reduced ROS-mediated phosphorylation of mitogen-activated protein kinase (MAPK) extracellular signal-regulated kinase 1/2 (Erk1/2) and c-Jun NH (2)-terminal kinase (JNK) that were also activated in PM exposed cells. MC further inhibited the secretion of pro-inflammatory cytokines (IL-6, IL-1β and IL-33) in MLE-12 cells exposed to PM. These results provide a clear evidence for MC’s potential in attenuating PM-triggered inflammatory responses in MLE-12 cells via repressing TLR2/4/7 and MAPK signaling. Therefore, MC can be developed as a therapeutic agent against PM induced airway inflammatory responses.