title: Antimicrobial activity of a neem cake extract in a broth model meat system.
abstract: This work reports on the antimicrobial activity of an ethyl acetate extract of neem (Azadirachta indica) cake (NCE) against bacteria affecting the quality of retail fresh meat in a broth model meat system. NCE (100 µg) was also tested by the agar disc diffusion method. It inhibited the growth of all tested microorganisms. The NCE growth inhibition zone (IZ) ranged 11.33-22.67 mm while the ciprofloxacin (10 µg) IZ ranged from 23.41-32.67 mm. There was no significant difference (p ≤ 0.05) between the antimicrobial activity of NCE and ciprofloxacin vs. C. jejuni and Leuconostoc spp. The NCE antibacterial activity was moreover determined at lower concentrations (1:10-1:100,000) in micro-assays. The percent growth reduction ranged from 61 ± 2.08-92 ± 3.21. The higher bacterial growth reduction was obtained at 10 µg concentration of NCE. Species-specific PCR and multiplex PCR with the DNA dye propidium monoazide were used to directly detect viable bacterial cells from experimentally contaminated meat samples. The numbers of bacterial cells never significantly (p ≤ 0.05) exceeded the inocula concentration used to experimentally contaminate the NCE treated meat. This report represents a screening methodology to evaluate the antimicrobial capability of a herbal extract to preserve meat.
authors.affiliation: Agricultural Research Council, Research Centre Animal Production and Genetic Improvement, Via Salaria 31 Km 26, Monterotondo 00015 RM, Italy. paola.delserrone@entecra.it
authors.forename: Paola
authors.initials: P
authors.lastname: Del Serrone
authors.forename: Marcello
authors.initials: M
authors.lastname: Nicoletti
mesh_terms: D000085:Acetates; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D031601:Azadirachta; D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development; D002167:Campylobacter / Q000187:drug effects; D056573:Carnobacterium / Q000187:drug effects; D002417:Cattle; D002939:Ciprofloxacin / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects; D007778:Lactobacillus / Q000187:drug effects; D007934:Leuconostoc / Q000187:drug effects; D008460:Meat / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000494:pharmacology*; D013210:Staphylococcus / Q000187:drug effects
chemical_list: D000085:Acetates; D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D002939:Ciprofloxacin; C007650:ethyl acetate
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