Bacteriological Control of Food Equipment Surfaces by Cleaning Systems. I. Detergent Effects

Area of Science:

• Food Safety and Hygiene
• Microbiology
• Surface Science

Background:

• Maintaining hygienic stainless steel surfaces is critical in food processing environments.
• Understanding the efficacy of different cleaning system components against bacterial contamination is essential.

Purpose of the Study:

• To evaluate the effectiveness of a cleaning simulator in assessing soil and bacterial load changes on stainless steel.
• To determine the impact of various cleaning system components (detergent, sanitizer, rinses) on controlling Streptococcus faecalis.

Main Methods:

• A cleaning simulator subjected stainless steel surfaces to 36 soiling and washing cycles.
• Four distinct cleaning systems were tested, varying in the inclusion of iodophor rinse, alkaline detergent, and water rinses.
• Milk inoculated with Streptococcus faecalis was used as the soil, with bacterial counts monitored throughout the cycles.

Main Results:

• The cleaning simulator effectively tracked changes in soil and bacterial numbers over time.
• Alkaline detergent was the most significant factor in reducing Streptococcus faecalis numbers.
• Sanitizer provided moderate bacterial control, whereas rinses demonstrated minimal effectiveness.

Conclusions:

• The efficacy of cleaning systems is primarily driven by the detergent's ability to remove soil and reduce bacteria.
• Bacterial numbers correlated with the amount of residual soil and the inhibitory effect of pre-wash solutions.
• Streptococcus faecalis did not proliferate during the 9.5-hour intercycle rest period under tested conditions.