Influence of different shrinking temperatures and vacuum conditions on the ability of psychrotrophic Clostridium to cause 'blown pack' spoilage in chilled vacuum-packaged beef.

This study determined the ability of psychrotrophic Clostridium strains isolated from vacuum-packaged beefs and abattoir environments to cause 'blown-pack' spoilage of vacuum-packaged beef stored at 2 and 15 °C. The influence of shrinking temperatures (83, 84 and 87 °C) and vacuum pressure (6 and 9 mbar) on the occurrence of such spoilage as well as the effects of simulated transportation (500 km) on the integrity of packages was determined. At 15 °C and 2 °C, twelve and six strains caused 'blown-pack' spoilage, respectively. The combination of vacuum pressure (9 mbar) combined with shrinking temperature (87 °C) retarded the occurrence of spoilage. The simulated transportation under the experimental conditions did not affect the integrity of packages. More studies that assess the factors that may contribute for the occurrence of 'blown-pack' spoilage should be performed to avoid the occurrence of such spoilage during its shelf-life.

Involvement of Clostridium gasigenes and C. algidicarnis in 'blown pack' spoilage of Brazilian vacuum-packed beef.

The objectives of this study were to isolate psychrotrophic clostridia from Brazilian vacuum-packed beef cuts (spoiled or not) and to identify the isolates by using 16S rRNA gene sequencing. Anaerobic psychrotrophic microorganisms were also enumerated and samples were collected to verify the incidence of psychrotrophic clostridia in the abattoir environment. Vacuum-packed beef cuts (n=8 grossly distended and n=5 non-spoiled) and environmental samples were obtained from a beef packing plant located in the state of São Paulo, Brazil. Each sample was divided in three subsamples (exudate, beef surface and beef core) that were analyzed for vegetative forms, total spore-forming, and sulfide reducing spore-forming, both activated by alcohol and heat. Biochemical profiles of the isolates were obtained using API20A, with further identification using 16S rRNA gene sequencing. The growth temperature and the pH range were also assessed. Populations of psychrotrophic anaerobic vegetative microorganisms of up to 10(10)CFU/(g, mL or 100 cm(2)) were found in 'blown pack' samples, while in non-spoiled samples populations of 10(5)CFU/(g, CFU/mL or CFU/100 cm(2)) was found. Overall, a higher population of total spores and sulfide reducing spores activated by heat in spoiled samples was found. Clostridium gasigenes (n=10) and C. algidicarnis (n=2) were identified using 16S rRNA gene sequencing. Among the ten C. gasigenes isolates, six were from spoiled samples (C1, C2 and C9), two were isolated from non-spoiled samples (C4 and C5) and two were isolated from the hide and the abattoir corridor/beef cut conveyor belt. C. algidicarnis was recovered from spoiled beef packs (C2). Although some samples (C3, C7, C10 and C14) presented signs of 'blown pack' spoilage, Clostridium was not recovered. C. algidicarnis (n=1) and C. gasigenes (n=9) isolates have shown a psychrotrophic behavior, grew in the range 6.2-8.2. This is the first report on the isolation of psychrotrophic Clostridium (C. gasigenes and C. algidicarnis) in Brazil. This study shows that psychrotrophic Clostridium may pose a risk for the stability of vacuum-packed beef produced in tropical countries during shelf-life and highlights the need of adopting control measures to reduce their incidence in abattoir and the occurrence of 'blown pack' spoilage.

Effect of NFkappaB inhibition by CAPE on skeletal muscle ischemia-reperfusion injury.

BACKGROUND/AIMS: Nuclear factor kappa B (NFkappaB) plays important role in the pathogenesis of skeletal muscle ischemia/reperfusion (I/R) injury. Caffeic acid phenyl ester (CAPE), a potent NFkappaB inhibitor, exhibits protective effects on I/R injury in some tissues. In this report, the effect of CAPE on skeletal muscle I/R injury in rats was studied. METHODS: Wistar rats were submitted to sham operation, 120-min hindlimb ischemia, or 120-min hindlimb ischemia plus saline or CAPE treatment followed by 4-h reperfusion. Gastrocnemius muscle injury was evaluated by serum aminotransferase levels, muscle edema, tissue glutathione and malondialdehyde measurement, and scoring of histological damage. Apoptotic nuclei were determined by a terminal uridine deoxynucleotidyl transferase dUTP nick end labeling assay. Muscle neutrophil and mast cell accumulation were also assessed. Lipoperoxidation products and NFkappaB were evaluated by 4-hydroxynonenal and NFkappaB p65 immunohistochemistry, respectively. RESULTS: Animals submitted to ischemia showed a marked increase in aminotransferases after reperfusion, but with lower levels in the CAPE group. Tissue glutathione levels declined gradually during ischemia to reperfusion, and were partially recovered with CAPE treatment. The histological damage score, muscle edema percentage, tissue malondialdehyde content, apoptosis index, and neutrophil and mast cell infiltration, as well as 4-hydroxynonenal and NFkappaB p65 labeling, were higher in animals submitted to I/R compared with the ischemia group. However, the CAPE treatment significantly reduced all of these alterations. CONCLUSIONS: CAPE was able to protect skeletal muscle against I/R injury in rats. This effect may be associated with the inhibition of the NFkappaB signaling pathway and decrease of the tissue inflammatory response following skeletal muscle I/R.