The antioxidant and antimicrobial effects of commercially available oil-soluble rosemary extracts VivOX 20 and VivOX 4 were investigated against lipid oxidation and microbial growth in vacuum-packed chicken frankfurters. The content of the main active ingredient, carnosic acid, in extracts was 20% and 4% (w/w), respectively. For comparison, the activity of commercially available preservative Robin LI LS was also tested. The control was chicken frankfurters made without test additives. Antioxidant activity tests were performed at 3 storage temperatures (4, 12, 25 • C), using the Rancimat method. Antimicrobial effect was investigated by aerobic plate count. Results showed that both rosemary preparations possess antioxidant and antimicrobial properties that may make them useful in the food industry. In chicken frankfurters with added VivOX 20 and VivOX 4, higher oxidative stability was exhibited at all storage temperatures, as in frankfurters with Robin LI LS. Addition of VivOX 20, VivOX 4, and Robin LI LS also significantly reduced the aerobic plate count, compared to controls, stored at 4 or 12 • C.Rosemary extracts VivOX 20 and VivOX 4 (patent WO 0049115, Knez and others 2000) were obtained from Vitiva (Markovci, Slovenia). VivOX 20 contains, according to the supplier's product specification, 95% of rosemary extract (total antioxidants > 23%) and SiO 2 (< 5%), while VivOX 4 contains 20% of rosemary extract (total antioxidants > 6%), 7% of SiO 2 , and 73% of NaCl. The content of the main active ingredient, carnosic acid, in the VivOX 20 and VivOX 4 is 20% (w/w) and 4% (w/w), respectively. Preservative Robin LI LS was purchased from Dera Food Technology N. V. (Bornem, Belgium). The main ingredients in Robin LI LS, according to the supplier's product specification, are sodium acetate, salt, and polyphosphate. The vacuum-packed chicken frankfurters were produced in Perutnina Ptuj (Ptuj, Slovenia) and contained approximately 25% fat.
