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Document Type:Latin Dissertation
Language of Document:English
Record Number:53659
Doc. No:TL23613
Call number:‭3289178‬
Main Entry:Amit Pal
Title & Author:Shelf life evaluation of ready-to-eat meat and poultry products based on Listeria monocytogenes growthAmit Pal
College:University of Minnesota
Date:2007
Degree:Ph.D.
student score:2007
Page No:270
Abstract:Strain variability, temperature, formulation and background microflora of food, packaging, and inoculum sizes are important factors affecting the growth of foodborne pathogen Listeria monocytogenes in ready-to-eat (RTE) meat and poultry products. The goal of the present study was to determine the growth kinetic parameters of L. monocytogenes in RTE foods as affected by these factors to establish the basis of a safety-based shelf life model. Growth of 19 L. monocytogenes in complex media, frankfurter slurries and turkey breast slurries were monitored at 4, 8, and 12°C and the effect of potassium lactate (PL) and sodium diacetate (SD) addition was assessed. Four models (one linear and three non-linear) were tested for curve fitting using F-test. The non-linear Baranyi-Roberts model was selected as the best fitting model. Three strains that were among the fastest or the slowest in liquid media were selected for challenge studies in three RTE meat products: cured frankfurters, sliced cured ham, and sliced uncured turkey breast. The specific levels within RTE meats were control, high pressure processed (HPP), and formulation with PL/SD. L. monocytogenes and psychrotrophic microflora were monitored at 4, 8, and 12°C and the treatment effects were analyzed using mixed-proc ANOVA. Results showed that the inhibitory effect of PL/SD was significantly dependent on temperature, strain, and product type (P < 0.05). Strain DUP-1044A was more resistant than other strains against similar formulation and temperature. DUP-1044A was more capable of growing on PL/SD-containing sliced ham than on frankfurters supplemented with those antimicrobials ( P < 0.05). In products without PL/SD, prolific pathogen and psychrotrophs growth (>6-logs) were observed within the commonly used shelf life (60 to 90 days). In general, growth was faster in HPP-treated samples than in controls. Finally, the time-to-detect L. monocytogenes was estimated in control frankfurters with inoculum sizes from 0.1 to 0.007 CFU/g. A safety-based shelf life model was constructed to predict the potential for detection of L. monocytogenes on frankfurters at 4, 8 and 12°C. The findings of the current research will be useful in developing a safety-based shelf life model for the RTE meat and poultry products.
Subject:Biological sciences; Listeria monocytogenes; Meat; Poultry products; Shelf life; Food science; 0359:Food science
Added Entry:F. L. Diez-Gonzalez, Theodore Peter
Added Entry:University of Minnesota