INTRODUCTION

This chapter is intended to be used as a risk-based test for the detection of microbial contamination in short-life products and encompasses short shelf-life products and/or short manufacturing times where the product must be administered as soon as possible. (See Rapid Microbiological Methods for the Detection of Contamination in Short-Life Products—A Risk-Based Approach 〈1071〉 for more details.) It may also be used as an in-process control for the testing of product intermediates, cell media, or process solutions. Growth-based methods using detection signals other than visible signs of microbial growth or precipitation within the culture media (i.e., turbidity, pellicle formation, or floccular growth) include adenosine triphosphate (ATP) bioluminescence measurement for the detection of growth in liquid culture media (nutrient broth) or the detection of colonies on membranes placed on solid culture media. All viable cells, including microorganisms, contain ATP at various levels. ATP bioluminescence detection of microorganisms is based on the luciferin-luciferase cascade emitting light that is measured with optical means (e.g., luminometer). Measured light is interpreted in a readout signal such as relative light units (RLU) or counts per charge coupled device (CCD) pixel.