18D-18 |
|
N. L. RAMÍREZ-CHAVARIN1, E. Ponce-Alquicira1, I. Guerrero-Legarreta2, M. C. Wacher-Rodarte3, A. Totosaus-Sánchez4, and M. L. Pérez-Chabela2. (1) Dept. de Biotecnología, Univ. Autónoma Metropolitana, Iztapalapa, Apartado Postal 55-535, Mexico D.F., 09340, Mexico, (2) Dept. de Biotecnología, Univ. Autónoma Metropolitana, Iztapalapa, Apartado Postal 55-535, Mexico D.F., 09340, Mexico, (3) Departamento de Alimentos, Facultad de Química, Univ. Nacional Autónoma de México, Ciudad Univ., Mexico D.F., Mexico, (4) Tecnológico de Estudios Superiores de Ecatepec, Subdirección de Investigación., Av. Valle del Mayo esquina Av. Hank González. Colonia Valle de Anáhuac, Ecatepec, Estado de México, 55210, Mexico Lactic acid bacteria in foods include cocci of genus Lactococcus, Streptococcus, Pediococcus and Leuconostoc, and bacilli of genus Lactobacillus and Carnobacterium. These bacteria metabolize sugars into organic acids promoting pH decrease. However, they also produce a variety of low molecular weight antimicrobial compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reuterin. When lactic acid bacteria are subjected to temperatures above the optimum growth range, physiological and morphological changes occur resulting in enzyme activity reduction. The objective of this work was to study the effect of heat resistant lactic acid bacteria on increasing shelf life of pork batters. Strains isolated from meat and meat products, previously identified as heat resistant, were inoculated in uncooked pork batters (5% w:w). Once cooked, the product was divided into three batches for microbial, sensory and physicochemical analysis. Samples were vacuum-packed and stored at 4oC for 15 days. Fifty untrained panelists carried out sensory evaluation at day 2 of storage; the analyzed variables were color, overall acceptability, tenderness and flavor. Enterobacteria counts as well as instrumental color (Hunter Lab) and texture (compression) were also analyzed. The control was uninoculated pork batters. Enterobacteria count decreased one log cycle during the first 8 days of storage, constant values were observed from then up to the end of storage; the highest count was 105 cfu/g, below the legal limit accepted by the Mexican legislation for this type of products. Overall acceptability and flavor of inoculated samples were significantly different to control samples, in agreement with other authors who reported improved sensory attributes of cooked meat products previously inoculated with lactic acid bacteria in addition of a decrease of L. monocytogenes and E. coli counts. No significant difference was observed with respect to texture. Conversely, significant differences were observed in color coordinates (Lab) as compared to the control, which showed higher paleness. Inoculation of lactic acid bacteria to uncooked batters would be a means to increase cooked sausage shelf life, decreasing enterobacteria counts without considerably affecting sensory characteristics.
Session 18D, Food Microbiology: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |