Abstract

Effect of MAP and Multi-layer Flexible Films on the Growth of Aerobic Bacteria of Fresh Ostrich Meat

The effect of different concentrations of two gas mixture (Carbon dioxide, Nitrogen), and also vacuum conditions and the usage of flexible multi-layer films has been studied on the growth of aerobic bacteria in fresh meat ostrich at refrigerator (T=4 0C). Ordinary conditions as a control packaging were compared with three types of modified atmosphere packaging: {(N270% + CO230%), (N230% + CO270%)} and vacuum conditions in this study. Fresh ostrich meat were packaged into 3 kinds of polymeric flexible pouch” 4-layers {PET (12) / AL (7) / PET (12) / LLD (100)}, 3-layers {PET (12) / L (12) / LLD (100)} and 3-layers {PET (12) / AL (7) / LLD (100)}. Samples were performed microbial tests (Total count of aerobic bacteria), in different times during 15 days, with 12 treatment ,3 run, statistical analysis and comparison of data, were done by software SAS (Ver:9/1) and Duncan’s new multiple range test, with confidence level of 95% (P <0.05) . The usage of MAP was not adequate for controlling spoilage, but the spoilage process was delayed. Aerobic bacteria’s grew in fresh ostrich meat, and their population under (% 30 CO2 +% 70 N2) and also vacuum conditions in these containers were more than 106 (not acceptable).However, the best condition belonged to (N2 30% N2+ 70% CO2), which was acceptable. The Characteristic of these multilayer flexible pouches (3-4 layers) with less water vapor and oxygen permeability, caused to control some chemical reactions and microbial growth in samples. Maximum aerobic bacteria’s which were grown in these meat samples was related to control conditions, then treatments under vacuum and % 30 CO2 in 3-layers AL (7 μ), and the lowest growth belonged to treatment under % 70 CO2 in 4-layer because of thickness and low steam permeability of this 4-layer container and anti-bacterial properties of more percentage of CO2.

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