RESUMO
This study evaluated the effects of freezing, prior to and after dry aging, on the microbiological and physical-chemical quality of beef. Strip loins (nâ¯=â¯24) from 12 carcasses were assigned to four treatments: non-frozen dry aging (Dry); dry aging, steak fabrication, freezing and slow thawing (Dryâ¯+â¯ST); freezing, fast thawing (FT; 20⯰C/15â¯h) and dry aging (FTâ¯+â¯Dry); freezing, slow thawing (ST; 4⯰C/48â¯h) and dry aging (STâ¯+â¯Dry). Freezing conditions wereâ¯-â¯20⯰C/28â¯days and dry aging conditions were 2⯰C/70% relative humidity, for 28â¯days. Freezing prior to dry aging did not affect the microbial counts compared to Dry. However, FTâ¯+â¯Dry and STâ¯+â¯Dry increased (16%) total process loss (Pâ¯<â¯.05) compared to Dry and Dry+ST. Moreover, freezing changed volatile compounds profile. Thus, freezing prior to dry aging was not a feasible process due to increased process loss, while freezing after dry aging was considered a viable alternative to preserve the steaks without compromising beef physical-chemical traits.
Assuntos
Manipulação de Alimentos/métodos , Microbiologia de Alimentos/métodos , Qualidade dos Alimentos , Congelamento , Carne Vermelha/análise , Carne Vermelha/microbiologia , Animais , Bovinos , Cor , Armazenamento de Alimentos/métodos , Concentração de Íons de Hidrogênio , Fenômenos Físicos , Resistência ao Cisalhamento , Substâncias Reativas com Ácido Tiobarbitúrico/química , Fatores de Tempo , Água/químicaRESUMO
The objective of this study was to evaluate the effect of different dry aging temperatures on the behavior of Listeria innocua used as a surrogate of L. monocytogenes. The process was performed in boneless loin pieces for up to 42â¯days at 2 and 8⯰C. The behavior of L. innocua was influenced by the temperature, aging time, and the water activity of the beef surface (Pâ¯<â¯.05). After 42â¯days, reductions of 2.38 and 3.37 log cfu/g were obtained on the beef surface aged at 2 and 8⯰C, respectively. According to data predicted by the Weibull model, the samples aged at 2⯰C would achieve a 4-log reduction with twice the time required for the process at 8⯰C. After trimming, 66.7% of the samples aged at 2⯰C were positive for L. innocua, whereas at 8⯰C the rate was 33.3%. Therefore, the results showed that the increase of process time and temperature as well by decrease of the aw reduces L. innocua counts.