|Hinton, Jr, Arthur|
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/13/2009
Publication Date: 8/1/2009
Citation: Ruiz, A., Williams, S.K., Hinton Jr, A., Rodrick, G., Djeri, N. 2009. Nisin, rosemary and ethylenenediaminetetraacetic acid affect the growth of listeria monocytogenes on ready-to-eat turkey ham stored at four degrees celsius for sixty-three days. Poultry Science. 88:1765-1772.
Interpretive Summary: Listeria monocytogenes is a major cause of human foodborne diseases associated with refrigerated, ready-to-eat meats that are contaminated by this pathogenic bacterium. The present study was conducted to examine the ability of nisin, rosemary, and ethylenenediaminetetraacetic acid (EDTA) to inhibit growth of Listeria on ready-to-eat, diced turkey ham. The turkey hams were cut into pieces and inoculated with Listeria bacteria. Inoculated ham samples were treated with either nisin; EDTA; rosemary; nisin and EDTA; nisin and rosemary; EDTA and rosemary; or nisin, EDTA and rosemary. Treated samples were vacuum packaged and refrigerated for up to 63 days. Each week, stored samples were analyzed to determine the number of Listeria bacteria, total bacteria, and lactic acid bacteria present. Nisin; nisin and rosemary; nisin and EDTA; and nisin, rosemary, and EDTA were effective in reducing the population of Listeria bacteria and total bacteria on the ham samples during storage. EDTA, rosemary, or EDTA and rosemary were not ineffective in inhibiting growth of Listeria bacteria during storage. Treatments containing nisin and EDTA were effective in reducing growth of lactic acid bacteria on the ham during storage. Results from this study indicate that nisin alone or in combination with rosemary and/or EDTA can be used to reduce growth of Listeria bacteria in ready-to-eat turkey ham.
Technical Abstract: The objectives of this study were to determine the anti-Listeria and general antimicrobial properties of nisin, rosemary, and ethylenenediaminetetraacetic acid (EDTA) alone and in combination on Listeria monocytogenes inoculated on ready-to-eat vacuum packaged diced turkey ham, and to ascertain the effects of the treatments on pH and objective color. The turkey hams were cut into 0.5 cm pieces, inoculated with a L. monocytogenes cocktail containing five strains of the bacterium, and treated with either no treatment and no inoculum (negative control), inoculum only (positive control), 0.5% nisin, 20mM EDTA, 1% rosemary, 0.5% nisin + 20mM EDTA, 0.5% nisin + 1% rosemary, 0.5% nisin + 20mM EDTA + 1% rosemary, or 20mM EDTA + 1% rosemary. All samples were vacuum packaged, stored for 63 days at 4 °C ± 1 and analyzed at one week intervals for total aerobes, L. monocytogenes, lactic acid organisms, pH and objective color. Nisin, nisin with rosemary, nisin with EDTA and nisin with rosemary and EDTA treatments reduced (P < 0.05) L. monocytogenes counts by 4.42, 4.20, 3.73, and 4.11 log cfu/g when compared to the positive control, respectively, on Day 0. L. monocytogenes counts remained less than 2.75 log cfu/g for ham treated with nisin. The EDTA and rosemary treatments alone and in combination were ineffective in inhibiting growth of L. monocytogenes. Although none of the treatments completely eliminated L. monocytogenes, the results indicated that ready-to-eat turkey ham will have significantly fewer L. monocytogenes when treated with nisin alone or in combination with rosemary and/or EDTA.