RESUMO
Beef livers from freshly slaughtered cattle were inoculated with coagulase-positive Staphylococcus aureus and then placed in frozen storage. After 14 d of frozen storage, one-half of the livers were subjected to 21°C for 24 h followed by a 15-d period of storage at -1°C. The other livers were kept in frozen storage (-29°C) during this 15-d period after which all livers were subjected to either 10 or 21°C temperatures. S. aureus counts did not change during the 15-d storage period at -1°C, whereas aerobic plate counts (APC) increased by over 3 log10 cycles. The low storage temperature plus the growth of competitor bacteria most likely prevented S. aureus from proliferating. When all livers were subjected to 24 to 144 h of storage at either 10 or 21°C, those that had been subjected to 15 d of slow surface thawing displayed a lower S. aureus count and higher APC than livers subjected to rapid thawing followed by holding at the high temperatures. This may mean that if livers become contaminated with substantial numbers of S. aureus before freezing, then rapid thawing coupled with high storage temperatures (more typical of meat merchandising in less developed countries) could allow for rapid S. aureus growth before competitor organisms increase in numbers.
RESUMO
The effects of transcontinental (interstate) transport and transoceanic shipment were determined on microbiological and shelf-life characteristics of beef tongues and livers. These variety meats were evaluated for both microbiological and shelf-life characteristics following slaughter in Guymon, Oklahoma, USA. The samples were then frozen and sent by refrigerated truck (4·5°C) to storage facilities in Jacksonville, Florida, USA. Further microbiological and shelf-life evaluations took place prior to overseas shipment at the University of Florida and following overseas shipment at The Institute CIVO-Technology, TNO, Zeist, The Netherlands. Aerobic plate counts (APCs) at 35°C for beef tongues showed a significant (P < 0·0.5) decrease following overseas shipment. Similar results were noted for beef livers. For both organs, the surface thawing in Florida, required for sampling, did not appear to affect the final bacterial counts. The 20°C APCs for beef tongues revealed a significant (P < 0·0.5) decrease following interstate transport but not transoceanic shipment. The 20°C APCs for beef livers did not differ significantly during the entire transportation period. The colour differences noted during transport of the product were probably the result of freezing and not of the actual shipping and storage conditions.
RESUMO
Effects of various handling, packaging, temperature-abuse and storage conditions were determined on the microbiological characteristics of beef livers and tongues. These organs were evaluated: (a) initially following slaughter, (b) immediately following the frozen storage period of 2-4 weeks at -29°C and (c) following a simulated shipping-temperature abuse of 24 h at 22-28°C followed by 13 days of storage at -1 ± 0.5°C. Initial counts (log/cm2) of coliforms, coagulase-positive Staphylococcus aureus and Clostridium perfringens ranged from 0.19-1.37. Generally, neither freezing nor temperature-abuse had a significant effect on these microorganisms. Vacuum-packaged beef tongues and livers, generally, had lower bacterial counts than did either naked or polyvinyl chloride film-wrapped products. Generally, it was observed that abusive storage temperatures, in conjunction with the naked and film-wrapped packaging systems, appear to present potential microbial spoilage problems when compared with vacuum packaging.
RESUMO
The microflora associated with fresh and temperature abused beef livers, kidneys, hearts, tongues and pork livers was identified. Variety meats were obtained from a packing plant and allocated to three packaging treatments, i.e., vacuum packaging, polyvinyl chloride film wrapping and no wrapping (unwrapped). Isolates were characterized from fresh variety meats following frozen storage for three weeks at -29 ± 2 C; and following simulated temperature abuse. Classification of 1555 isolates obtained from aerobic plate counts at 35, 20 and 7 C is provided. Fresh variety meats were found to be contaminated with a variety of bacteria commonly associated with fresh red meats immediately post-mortem, with Micrococcus sp. being the most frequently isolated gram-positive bacterium and Escherichia coli the predominating gram-negative isolate. Frozen variety meats before simulated temperature abuse reflected a higher proportion of gram-positive organisms and fewer Enterobacteriaceae than fresh variety meats. Abused variety meats yielded predominately Pseudomonas strains, except where vacuum packaging was used, in which case isolates were predominately Lactobacillus sp. and Micrococcus .
