Survival of Arcobacter butzleri on vacuum packaged chill stored beef

Abstract

The ability of Arcobacter butzleri to survive and the effect of initial cell numbers on their survival on vacuum packed chill stored beef were examined. In addition, the effect of natural microflora present on commercial beef on the survival of A. butzleri under vacuum packaged chill stored conditions was also examined. The numbers of A. butzleri on sterile beef cores stored under vacuum packaged conditions at −1.5 or 4°C dropped significantly (P<0.05) over the time of the study (6wks). In contrast, survival of A. butzleri on commercial vacuum packaged beef (beef with natural microflora) was significantly (P<0.05) enhanced, resulting in only 0.3 and 1.3logcfucm−2 drops in numbers at −1.5°C and 4°C, respectively, at the end of 6wks. Survival of A. butzleri on sterile beef cores inoculated with higher initial numbers was significantly (P<0.05) higher than on core inoculated with lower initial numbers, while on commercial vacuum packaged beef initial A. butzleri numbers had no significant (P>0.05) effect on its survival. Cores inoculated with ~106cfucm−2A. butzleri, irrespective of storage temperature or packaging conditions, could be enumerated by direct plating up to day 35. However, cores inoculated with ~104cfucm−2, irrespective of packaging conditions, A. butzleri could be enumerated by direct plating up to 28 and 21days from cores held at −1.5 and 4°C, respectively. On commercial vacuum packaged beef, irrespective of initial inoculated A. butzleri cell numbers or temperature of storage, A. butzleri could be enumerated by direct plating even at 6wks (end of the study). The presence of inoculated A. butzleri on commercial vacuum packaged beef, irrespective of the initial cell numbers had no significant (P>0.05) effect on the natural microflora numbers compared to uninoculated controls. These results show that natural microflora on commercial vacuum packaged beef afford enhanced survival of A. butzleri, irrespective of their initial cell numbers on the surface of beef stored at industry standard vacuum packaging and chill stored conditions. These findings reinforce the requirement for strict hygienic practices or the implementation of decontamination technologies to ensure safety of beef with respect to this pathogen.