Evaluation of an alcohol-based sanitizer spray's bactericidal effects on Salmonella inoculated onto stainless steel and shell egg processing equipment.

Authors: Musgrove, Michael; NORTHCUTT, JULIE - Clemson University

Submitted to: International Journal of Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2012
Publication Date: 4/30/2012
Citation: Musgrove, M.T., Northcutt, J. 2012. Evaluation of an alcohol-based sanitizer spray's bactericidal effects on Salmonella inoculated onto stainless steel and shell egg processing equipment. International Journal of Poultry Science. 11(2):92-95.

Interpretive Summary: Packer head brushes are one of the last pieces of automatic washing, grading, and packing machinery to contact shell eggs after they have been washed and graded. Most pieces of equipment in shell egg washing facilities are constructed at least in part with stainless steel materials. Though intact shell eggs are less perishable than meat, facility sanitation is still important in terms of decreasing the risk of egg-borne illness. There are few reports on procedures or materials used to sanitize shell egg processing equipment. This study was conducted to determine the efficacy of washing with water and/or sanitizing with a solution of alcohol and quaternary ammonium. It was determined that water alone removed some bacteria. However, the sanitizer was 100-1000x more effective at reducing Salmonella cells used to inoculate stainless steel or packer head brushes in a laboratory setting. Within 5 min Salmonella was reduced 100 fold and eliminated after 24 h. On packer head brushes, there was no reduction after 5 min but there were no positives after 24 h. This information can be used by sanitation officers or plant managers in the egg industry and by researchers studying sanitation.

Technical Abstract: . Improved sanitation procedures may reduce the risk of food-borne illness . Experiments were conducted to determine the ability of an alcohol-quaternary ammonium sanitizer or water to reduce Salmonella inoculated onto stainless steel and shell egg processing equipment. A nalidixic acid-resistant Salmonella Typhimurium (ST) was grown on agar plates at 37°C for 18-24 h, cells were harvested and added to phosphate buffered saline (PBS) to generate 8.5 Salmonella cells/mL inoculum in each of two repetitions. Both experiments were repeated twice. In the first experiment four stainless steel beakers were contaminated by spraying 10 mL of inoculum, respectively. Beakers were 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). After 5 min and 24 h each beaker was swabbed with a PBS moistened sponge and plated onto BGS supplemented with 200 ppm nalidixic acid to enumerate surviving ST. In the second experiment, inoculum was sprayed onto two brushes from shell egg packing machinery. After 15 min, 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 after 5 min and 24 h. For stainless steel, after 5 min, 5.5 and 3.0 log CFU/mL ST and after 24 h, 2.8 and 0.0 log CFU/mL ST were recovered from stainless steel, respectively. Packer head brush average results were 4.7 and 3.1 log CFU/mL ST after 5 min and were 4.0 and 0.00 log CFU/ml ST after 24 h. This sanitizer solution and delivery system were 100 to 10,000 times more effective than water in reducing Salmonella numbers. Key Words: eggs, sanitation, Salmonella, stainless steel, packer head brushes