Abstract:Fresh beef is perishable product, which is an ideal substrate for the growth of spoilage microorganisms. Thus, it is essential to apply adequate preservation technologies to retard the bacterial spoilage and maintain beef quality and safety. Super-chilled storage with an intense microbial growth delay, less protein denaturation and structural damage, was considered as an advantageous technology for meat products. Currently, this technology has been successfully applied in the preservation of beef, extending the shelf life up to 20 to 30 weeks. Excellent temperature control is critical to enable a long shelf life; Subtle differences in super-chilled temperature might exert a significant effect on shelf life of meat products. The application of super-chilled storage in domestic meat industry is scarce, due to the restriction of technology and equipment in China. Temperature fluctuation is the major issue in domestic commercial super-chilled condition, which may affect the meat products quality during storage. However, little information is available looking at the effects of commercial super-chilled condition on beef quality during long term storage. Therefore, this study aimed to explore the effects of commercial super-chilled condition (-4-4 ℃) on beef quality during long term storage, with the comparison of the ideal super-chilled condition under lab control (-2-0 ℃). Physicochemical, microbial counts and sensory attributes of vacuum-packaged beef cuts stored under two conditions were analyzed during 20 weeks. The results showed that the L*, a* and b* values increased gradually over the entire storage time for both ideal and commercial super-chilled samples. Moreover, thiobarbituric acid reactive substances (TBARS) values of both samples exhibited slight changes over time, and were in the range of 0.19-0.35 mg/kg. Noteworthy, the different growth rates for total viable counts (TVC) and lactic acid bacteria (LAB) counts were found in different storage treatments. The TVC counts of the samples stored at commercial super-chilled condition grew more rapidly as compared to that in samples under ideal super-chilled condition, reaching 7.09 lg CFU/cm2 after 9 weeks. Whereas, the samples under ideal super-chilled condition were below the spoilage thresholds (7 lg CFU/cm2) during the entire storage period. For sensory evaluation, samples under ideal super-chilled condition showed better sensory attributes than those in commercial super-chilled condition at the 20th weeks of storage. One noticeable point in the present study was that samples from both storage treatments maintained high consumer acceptance (scores higher than 60) after 20 weeks storage, and exhibited longer shelf-life in term of sensory attributes. In addition, the TVB-N values of samples under commercial super-chilled condition exceeded the threshold (≤15 mg/100 g) at 9 weeks, reaching 15.59 mg/100 g. Compared to commercial super-chilled condition, ideal super-chilled condition exerted a better preservative effect for beef cuts, the TVB-N values reached 16.66 mg/100 g at 12 weeks. The present results here indicated that the acceptable shelf life of super-chilled beef cuts under ideal super-chilled and commercial super-chilled conditions were less than 12 weeks and 9 weeks, respectively, according to the Chinese National Food Safety Standard GB 2707-2016. Differences in temperature fluctuations during super-chilled storage and large temperature fluctuations during transportation had significant influences on beef quality and shelf life.