A Flooded Plate Loop Count Procedure ¹.

Area of Science:

• Microbiology
• Food Science
• Dairy Science

Background:

• Accurate microbial enumeration in milk is crucial for quality control and safety.
• Traditional plate loop count methods can sometimes yield uneven colony distribution.
• Standardization of microbiological testing procedures is essential for reproducible results.

Purpose of the Study:

• To describe a modified plate loop count procedure for analyzing milk samples.
• To evaluate the impact of the modified method on colony uniformity and statistical characteristics.
• To compare the results of the modified method with the conventional plate loop count.

Main Methods:

• A modified plate loop count procedure was developed using a 0.5-ml diluent loop-rinse onto pre-dried agar in a 100-mm petri plate.
• Milk samples were distributed using a glass spreader, followed by drying and standard incubation.
• The modified method was statistically compared to the conventional plate loop count method.

Main Results:

• The modified plate loop count procedure resulted in more uniform colony formation compared to the conventional method.
• The statistical characteristics of the plate loop count on raw milk samples were not significantly altered.
• A high correlation coefficient of 0.91 was observed between the modified (flooded) and conventional plate loop counts.

Conclusions:

• The modified plate loop count method offers improved colony uniformity for milk sample analysis.
• This technique provides a reliable alternative for bacterial enumeration in raw milk, maintaining statistical validity.
• The enhanced procedure is a valuable modification for routine microbiological testing in the dairy industry.