Related Experiment Video
Updated: Jun 17, 2026
Modified Most Probable Number Assay to Quantify Salmonella in Raw and Ready-to-Cook Chicken Products
Published on: January 31, 2025
A validated miniaturized MPN method, based on ISO 6579:2002, for the enumeration of Salmonella from poultry matrices
A Pavic1, P J Groves, G Bailey
1Birling Avian Laboratories, Bringelly, NSW, Australia. Tony_Pavic@baiada.com.au
Aims:
To validate the effectiveness of a miniaturized most probable number method (mMPN) in enumerating Salmonella from poultry matrices.
Methods And Results:
A MPN was developed, based on the ISO 6579:2002 method using modified semi-solid Rappaport-Vassiliadis media as the sole selective medium. The validation of the mMPN was shown to not differ significantly from, at the 95% confidence level (Student's t-test P = 0·357) to, the traditional 9-tube MPN (tMPN) using pure cultures of Salmonella ser. Typhimurium, Infantis, Montevideo, Muenster and Salmonella subsp II 1,4,12,27:b:[e,n,x] (Sofia). The validation of naturally and artificially contaminated poultry matrices (carcasses, scald tank water, faeces, caeca and feed) showed that detection using the mMPN compared well to the ISO 6572:2002; sensitivity (92%), specificity (97%) and agreement (KAPPA 0·72). The quantitative comparison between the tMPN and mMPN methods showed that 92% of enumerations were less than ± 1 log different (Student's t-test = 0·13). Financial analysis showed that the mMPN required 64% less media and 56% less labour than the tMPN.
Conclusion:
The mMPN is a consistent, easy to automate method for the enumeration of Salmonella from different poultry matrices.
Significance And Impact Of Study:
The miniaturized MPN reduces the material and labour cost of the method and enables the uniform and accurate measurement of the effectiveness of intervention strategies in the control of Salmonella colonization of poultry.
Insights
A miniaturized most probable number (mMPN) method accurately enumerates Salmonella in poultry. This validated method is cost-effective, requiring less media and labor than traditional techniques.
Area of Science:
- Microbiology
- Food Safety
- Veterinary Science
Background:
- Salmonella contamination in poultry poses a significant public health risk.
- Accurate enumeration of Salmonella is crucial for assessing food safety and intervention effectiveness.
- Traditional methods for Salmonella enumeration can be labor-intensive and costly.
Purpose of the Study:
- To validate a miniaturized most probable number (mMPN) method for Salmonella enumeration in poultry.
- To compare the mMPN method with traditional methods in terms of accuracy, sensitivity, and specificity.
- To assess the cost-effectiveness of the mMPN method.
Main Methods:
- Development of a miniaturized MPN (mMPN) method based on ISO 6579:2002.
- Validation using pure cultures of various Salmonella serotypes.
- Testing on naturally and artificially contaminated poultry matrices (carcasses, water, feces, ceca, feed).
- Comparison with traditional 9-tube MPN (tMPN) and ISO 6572:2002.
Main Results:
- The mMPN showed no significant difference from the traditional MPN (tMPN) for pure cultures (P = 0.357).
- Validation on poultry matrices demonstrated high sensitivity (92%), specificity (97%), and agreement (KAPPA 0.72) compared to ISO 6572:2002.
- Quantitative comparison showed 92% of enumerations were within ± 1 log difference (P = 0.13).
- The mMPN required 64% less media and 56% less labor than the tMPN.
Conclusions:
- The mMPN is a consistent and automatable method for Salmonella enumeration in poultry.
- This method offers reduced material and labor costs.
- The mMPN facilitates accurate measurement of Salmonella control strategies in poultry.
