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United States Department of Agriculture

Agricultural Research Service

Title: Evaluation of an Alcohol-Based Sanitizer Spray's Bactericidal Effects on Salmonella Inoculated onto Stainless Steel and Shell Egg Processing Equipment

item Musgrove, Michael

Submitted to: International Association for Food Protection Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 7/28/2010
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Introduction: Safety regulations are being drafted for the shell egg industry. Sanitation standard operating procedures are an important precursor to HACCP regulations. Salmonella is the pathogen was most often associated with egg-borne outbreaks. Developing effective sanitation procedures that will reduce Salmonella contamination of equipment or other surfaces in the processing environment may help to reduce consumer exposure even if eggs are not handled or cooked properly. Purpose: Experiments were conducted to determine the ability of a alcohol-quaternary ammonium sanitizer delivered in a mist to reduce Salmonella inoculated onto stainless steel and shell egg processing equipment. Methods: A nalidix acid-resistant Salmonella Typhimurium was grown on agar plates at 37°C for 18-24 h. Cells were harvested and added to phosphate buffered saline to generate inoculum with a density of ~100 billion cells/mL in each of two repetitions. Inoculum was added to a sterile spray bottle. Each of two experiments were repeated twice. In the first experiment the inside of four stainless steel beakers was inoculated by spraying 10 mL of inoculum, respectively. Excess liquid was decanted and the beaker was allowed to dry for 15 min. Two of the beakers were sprayed with 20 mL of water and the other two were sprayed with a sanitizer solution (70% isopropyl alcohol and 200 ppm quaternary ammonium. Sanitizer was delivered in a mist fine enough to spray onto water sensitive equipment. After five min. and 24 h each beaker was swabbed with a sponge moistened with phosphate buffered saline. After swabbing, sponge diluent was enumerated by plating serial dilutions onto BGS supplemented with 200 ppm nalidix acid. In the second experiment, the 10 mL of inoculum was sprayed onto each of two brushes used to transport washed shell eggs into cartons or flats. After drying for 15 minutes, one brush was sprayed with water for five min and the other was sprayed with the sanitizer for 30 s. Each brush was sampled by swabbing three times at the same time intervals as described previously. Results: After 5 min, on average 4.2 and 2.0 log CFU/mL Salmonella were recovered from stainless steel sprayed with water and sanitizer, respectively. After 24 h, 3.2 and 1.2 log CFU/mL were recovered, respectively. Packer head brush average results were 4.7 and 3.1 log CFU/mL Salmonella after 5 min and 4.0 and 0.00 after 24 h. Significance: Often, spraying with water is the sanitizing treatment after eggs are washed. This sanitizer solution and delivery system were 100 to 10,000 times more effective than water in reducing Salmonella numbers.

Last Modified: 10/17/2017
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