Models of Pseudomonas Growth Kinetics and Shelf Life in Chilled Longissimus dorsi Muscles of Beef |
Yimin Zhang, Yanwei Mao, Ke Li, Pengcheng Dong, Rongrong Liang, Xin Luo |
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Abstract |
The aim of this study was to confirm Pseudomonas spp. as the specific spoilage organism (SSO) of chilled beef during aerobic storage and to establish a model to predict the shelf life of beef. Naturally contaminated beef was stored at 4C, and the spoilage limit of Pseudomonas organisms was determined by measuring several quality indicators during storage, including the number of Pseudomonas organisms, total number of bacteria, total volatile basic nitrogen (TVBN) values, L value color scale scores and sensory evaluation scores. The beef was then stored at 0, 4, 7, 10, 15 or 20C for varying amounts of time, and the number of Pseudomonas organisms were counted, allowing a corresponding growth model to be established. The results showed that the presence of Pseudomonas spp. was significantly correlated to each quality characteristic (p<0.01), demonstrating that Pseudomonas spp. are the SSO of chilled beef and that the spoilage limit was 108.20 cfu/g. The Baranyi and Roberts equation can predict the growth of Pseudomonas spp. in beef, and the R2 value of each model was greater than 0.95. The square root model was used as follows, and the absolute values of the residuals were less than 0.05: max1/2 = 0.15604 [T+(-0.08472)] (p<0.01), R2 = 0.98, -1/2 = 0.0649+0.0242T (p<0.01, R2 = 0.94). The model presented here describes the impact of different temperatures on the growth of Pseudomonas spp., thereby establishing a model for the prediction of the shelf life of beef stored between 0 to 20C. |
Keywords:
Pseudomonas spp.; Chilled Beef; Model; Shelf life |
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