P3-78 Evaluation of the Aerobic Procedure for the Recovery of Lactic Acid Bacteria with 3M™ Petrifilm Plates™ in Ready-to-Eat Meat Products

Wednesday, July 31, 2013
Exhibit Hall (Charlotte Convention Center)
Guadalupe Mondragon, 3M Food Safety, Mexico City, Mexico
Pedro Duran, 3M Food Safety, Mexico City, Mexico
Olga Velazquez, UNAM, Mexico City, Mexico
Teresa Alvarez, Sigma Alimentos, Edo. de Mexico, Mexico
Introduction: The detection and enumeration of lactic acid bacteria (LAB) has relevance among ready-to-eat meat (RTE) products because LAB are responsible of food spoilage, causing the development of flavors, odors and gas which shortens the shelf life of this type of products. The use of alternative methods for this analysis could reduce the cost and time-to-results.

Purpose: The objective of this study was to evaluate the performance of the Aerobic Procedure for Lactic Acid Bacteria with 3M™ Petrifilm™ Aerobic Count Plates compared to the Agar method using acidified MRS (deMan, Rogosa and Sharpe) referred in the Compendium of Method for the Microbiological Examination of Foods.

Methods: A total of 53 samples from a mix of turkey and pork ham were artificially inoculated with LAB strains commonly found in these products (Leuconostoc mesenteroides and a mixture of Lactococcus lactis spp lactis and Lactobacillus brevis) at a medium level of 50-100 CFU/plate. Samples were analyzed in duplicate by standard plate count method using acidified MRS agar to pH 5.5 ± 1 and the Aerobic Procedure for LAB that utilizes the Petrifilm Aerobic Count Plate supplemented with MRS medium and a pH indicator to help identify and enumerate lactic acid bacteria.

Results: The counts from both methods were converted to log values and averaged. A paired t-test for two sample means was calculated to analyze statistical differences. Results do not show any significant differences (P = 0.56) between the methods, the Pearson correlation coefficient (r) was also determined showing a positive correlation (0.96).

Significance: Results shown that the Aerobic Procedure for the detection and enumeration of LAB is a reliable and easy method that reduces time for confirmation and cost of sample preparation by eliminating the materials needed to create an anaerobic environment.