Microbiology-PTM-OMA_Modules_1-5

Artificial Contamination of Foods

• Chop, cut, melt, temper, etc.

• Maintain the integrity of the matrix • Use the same lot of matrix for inoculated materials and noninoculated material • Do not dilute matrix with inoculum • For qualitative methods, inoculate:  • 1 material at a low level to achieve fractional positives • 1 material at a high level to aim for all positives (2‐5x inoculum of low level) • For quantitative methods, inoculate:

• 1 material at a low level within the method range • 1 material at a medium level within the method range • 1 material at a high level within the method range