Background & Aims: Beef meat is highly prone to microbial spoilage as it is rich in essential nutrients and putrefying in nature. Nowadays, consumers are applicant to usage of natural replacements causing to side effects of synthetic preservatives such as carcinogenicity and teratogenicity.

Materials & Methods: In this study the influence of hydro alcohol sumac extract (SE) and chitosan coating alone or in combination with Z. multiflora Boiss essential oil (ZEO) added, on microbial attributes of beef meat were investigated during refrigerated storage in normal and modified atmosphere packaging (MAP: 80% oxygen and 20% dioxide carbon). The samples were stored at 4 °C for 20 days and microbial analysis were conducted at zero, four, eight, 12, 16 and 20 days.

Results: Total viable counts, lactic acid bacteria, Pseudomonas spp., Enterobacteriaceae and yeasts- molds were significantly lower in all treatments than control over the storage time. The highest level of antimicrobial effect of chitosan, SE 4% and ZEO were found on TVC (by 3.69 and 4.04 log CFU/g (colony forming unit / gram) reduction compared with control), Enterobacteriaceae (3.61 and 3.73 log CFU/g reduction) and lactic acid bacteria (2.67 and 2.53 log CFU/g reduction), in normal packaging and MAP, respectively.

Conclusion: These results suggest the potential of chitosan, SE and ZEO as biopreservatives under refrigerated storage in normal packaging and MAP.