Olive leaf extract (OLE) has been used traditionally as a herbal supplement since it contains polyphenolic compounds with beneficial properties ranging from increasing energy levels, lowering blood pressure, and supporting the cardiovascular and immune systems. In addition to the beneficial effects on human health, OLE also has antimicrobial properties. The aim of this work was to investigate the antimicrobial effect of OLE against major foodborne pathogens, including Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Enteritidis. Our results demonstrated that at a concentration of 62.5 mg/ml, OLE almost completely inhibited the growth of these three pathogens. In addition, OLE also reduced cell motility in L. monocytogenes, which correlated with the absence of flagella as shown by scanning electron microscopy. Moreover, OLE inhibited biofilm formation in L. monocytogenes and S. Enteritidis. Taken together, OLE, as a natural product, has the potential to be used as an antimicrobial to control foodborne pathogens.

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a b s t r a c tAdding arbuscular mycorrhizal [AM] fungus inoculum to potting media enables vegetable farmers to better take advantage of the AM symbiosis. On-farm production of AM fungus inoculum is a viable alternative to commercially-available inocula. We conducted a seven year experiment at a conventional vegetable farm in southeastern Pennsylvania with high soil available P typical of the Mid-Atlantic region of the USA (210 mg kg −1 soil). Seedlings of three to seven cultivars of Solanum lycopersicum L. were inoculated in the greenhouse phase of production with a mixed species inoculum of AM fungi produced on-farm. Performance of the inoculation treatment was evaluated based on growth response in the greenhouse and fruit production in the field compared to uninoculated controls. Colonization levels were typically only 1-10% of root length at the time of outplanting. The mean mycorrhizal growth dependency based upon shoot growth at the time of outplanting was significant at 12.5 ± 3.55% (␣= 0.05). In addition, the mean mycorrhizal yield response over the seven year experiment was significant at 6.02 ± 1.92% (␣= 0.05). Routine use of AM fungus inoculum produced on-farm provided a modest but significant increase in yield of tomato fruit with minimal change in farm management even in a high P soil.Published by Elsevier B.V.