Final answer:
The federal limit for bacterial count in products like infant formula is determined to ensure consumer safety. Microbiologists use standard practices, including the 0.5 McFarland standard and the pour plate method, to measure bacterial concentration. The EPA sets enforceable standards like MCL for bacterial presence in various consumer products.
Step-by-step explanation:
The federal limit for the bacterial count in infant formula or similar products is critical to ensure the safety and health of consumers. Microbiologists work to maintain a uniform number of cells in each test by preparing bacterial cell suspensions and comparing them to a standard, such as the 0.5 McFarland standard. Furthermore, pour plate methods for determining the count of bacteria involve counting the number of colonies that typically range between 30-300 to ensure accuracy and statistical reliability. Exceeding 300 colonies can lead to inaccuracies due to multiple bacteria forming a single colony.
Significant figures in reporting numerical bacterial data are also important. As per the example, a microbiologist rounds the number of cells to 525,000 cells per liter from 525,341 to reflect the measurement's accuracy. When calculating CFU (Colony Forming Units) from dilutions, adjustments are made to account for the dilution factor. In the provided example, a count of 50 colonies from a 1:10,000 dilution and a volume of 0.1 mL leads to an estimation of 5 million cells/mL.
The federal limit for bacterial presence in consumer products is often set by agencies such as the EPA, which defines such limits through enforceable standards like the Maximum Contaminant Level (MCL) for various pollutants, including pathogens like bacteria.