Changes in Chilled Chicken Quality and Correlation Analysis during Different Shelf Life

[Objective] The paper was to study the change rule and correlation analysis of quality indexes of chilled chicken within 7 d shelf life.[Method] Six pieces of fresh breast muscle were packaged in polyethylene（PE） food storage bags,labeled,and refrigerated at 4 ℃.The p H,water loss rate,tenderness,color value and inosinic acid content of chicken were measured at different time points of preservation（cold storage for 0,1,2,3,6,7 d）.[Result] With the prolongation of shelf life,the p H of chilled chicken first increased then tended to be stable;the water loss rate first increased then stabilized;the shear force first decreased then increased.There was little difference in brightness value（L＊） of chilled chicken dur-ing different shelf life（P〉0.05）.The red degree value（a＊） decreased with the prolongation of shelf life;the yellow degree value（b＊） increased with the extension of shelf life.The inosinic acid content decreased with the prolongation of shelf life.The p H of chilled chicken in different shelf life had significant positive correlation with water loss rate（P〈0.05） and extremely significant negative correlation with shear force（P〈0.01）.[Conclusion]The shelf life of 7 d has impact on meat color and inosinic acid of chilled chicken.Cold fresh preservation of chilled chicken should be less than 6 d;p H has certain correlation with water loss rate and shear force.

Insight into the spoilage heterogeneity of meat-borne bacteria isolates with high-producing collagenase

Chilled chicken is inevitably contaminated by microorganisms during slaughtering and processing,resulting in spoilage.Cutting parts of chilled chicken,especially wings,feet,and other skin-on products,are abundant in collagen,which may be the primary target for degradation by spoilage microorganisms.In this work,a total of 17 isolates of spoilage bacteria that could secrete both collagenase and lipase were determined by raw-chicken juice agar(RJA)method,and the results showed that 7 strains of Serratia,Aeromonas,and Pseudomonas could significantly decompose the collagen ingredients.The gelatin zymography showed that Serratia liquefaciens(F5)and(G7)had apparent degradation bands around 50 kDa,and Aeromonas veronii(G8)and Aeromonas salmonicida(H8)had a band around.65 and 95 kDa,respectively.The lipase and collagenase activities were detected isolate-by-isolate,with F5 showing the highest collagenase activity.For spoilage ability on meat in situ,F5 performed strongest in spoilage ability,indicated by the total viable counts,total volatile basic nitrogen content,sensory scores,lipase,and collagenase activity.This study provides a theoretical basis for spoilage heterogeneity of strains with high-producing collagenase in meat.