1. Evaluation of chemical immersion treatments to reduce microbial counts in fresh beef
Ahmed Kassem1, Joseph Meade1, Kevina McGill1, James Gibbons1, James Lyng2, Paul Whyte1
1School of Veterinary Medicine, 2School of Agriculture and Food Science, University College Dublin.
Results
Introduction
1- each single chemical show significant reduction (P<0.01) in both concentrations to Campylobacter, Salmonella, and E coli.
2- LA (3% and 5%) and CA 3% were the only chemicals reduced TVC significantly while, only TSP in both concentrations give no significant difference when compared to control (P<0.01).
3- results show no difference between high (5%) and low (3%) concentrations.
4- For combinations using two chemicals only TVC ,Salmonella and Listeria populations were significantly reduced compared to single treatments (P<0.01).
Microbial contamination remains a major challenge in the meat industry. Contamination can lead to reduced shelf life and potentially compromise the safety of meat and meat products. As a result the meat industry is continually exploring technologies to mitigate these risks. Any potential technology should be cost effective, practical, safe and acceptable to the consumer, while also preserving the nutritional and sensory characteristics of the food.
The aim of this study was to assess the ability of a number of chemicals (acetic acid (AA), citric acid, (CA) lactic acid (LA), sodium decanoate (SD) and trisodium phosphate (TSP)) to reduce microbial populations (total viable count, Campylobacter jejuni, E coli, Salmonella Typhimurium, Listeria monocytogenes) on raw beef using an immersion system. Experiments were carried out to identify effective concentrations (3 and 5% for AA, CA, LA, SD and 10 and 12% for TSP) respectively, to reduce microbial loads. Possible synergistic effects of using two combinations of chemicals (LA+CA and LA+AA) were also investigated
Materials and Method
Samples Inoculation: Fresh beef was cut in to small pieces of 10 grams each. Three samples were used for each treatment and dipped for 60 seconds in overnight bacterial culture containing about 7 log cfu/ml of each bacterial species and left for 30 minutes allow time for attachment.
Chemical Treatment: Separate sample groups (n=3) were dipped in two different concentrations of each chemical solution for 1 minute (3% and 5% for AA, CA, LA, SD and 12% for TSP respectively). Following treatment, samples were immersed in distilled water for 15 seconds to rinse off any residual chemicals. Untreated control samples were immersed in distilled water only prior to microbiological analysis. For combined chemical treatments (LA+CA and LA+AA), samples were dipped in the first chemical solution and rinsed in water before immersion in the second solution to prevent any potential chemical interaction.
Each experiment was repeated 3 times in different occasions.
Microbiological Analysis: Samples were stomached for 30 seconds in 90 ml MRD and serially diluted (1:10) using MRD before plating onto mCCDA (Campylobacter), PCA (TVC), VRBGA + MUG (E coli), XLD ( Salmonella) and Listeria agar (Listeria) and incubated according to ISO methods.
Figure 1: show reduction in bacteria count produced by chemical treatments
Conclusions
The chemicals examined in this study were shown to be effective even at low concentrations and increasing concentrations to 5% did not result in significant further reductions.
Treatments can be applied in an immersion system to decrease bacterial loads on fresh beef.
Using combinations of chemical treatments enhanced reductions for TVC, Salmonella, and Listeria.
Acknowledgement
The authors wish to acknowledge the financial support of the Iraqi ministry of Higher Education and the University of Kufa