An interesting bit of Info from the Colgin Liquid Smoke site FAQ's...JJ
How can I use liquid smoke to prevent spoilage?
As you're well aware, smoking products adds flavor and color to them. But liquid smoke, which is generated from hardwood sawdust, also has antioxidative and antimicrobial properties as well. It's possible to add liquid smoke to meat products to improve their safety and shelf life. A variety of studies conducted at Kansas State University (Department of Animal Sciences and Industry, Manhattan, KS) have shown that liquid smoke eliminates E. coli 015 7:H7 and other pathogens.
Liquid smoke's functionality in meats is mostly the result of acetic, propionic and other organic acids that lower pH and destroy the walls of bacteria cells. The phenolic compounds in the smoke are well-known bactericides. In one of the university studies, researchers added liquid smoke to pathogenic bacteria in petri dishes, which inhibited microbial growth. The smoke also works well against Salmonella, Listeria and different spoilage organisms.
In other university experiments, scientists inoculated beef tissues and trimmings as well as ground beef with E. coli 0157:H7 and added various amounts of liquid smoke to the samples. The smoke reduced the amount of the bacteria on the surface of the meats. It appears that you can sterilize large meat trimmings by washing them with liquid smoke.
Because liquid smoke also functions as an antioxidant, it prevents warmed-over flavor (WOF) in products. WOF, common in cooked meat that is not consumed immediately, is caused by lipid oxidation reactions. Sensory and analytical studies indicated that the smoke eliminated WOF in ground beef patties. Researchers determined that levels of 0.5% to 1% liquid smoke were acceptable usage levels in these applications.