Contamination of the Deep Tissues of Carcasses by Bacteria Present on the Slaughter Instruments or in the Gut

Possible routes by which bacteria might reach the deep tissues of carcasses were tested by placing genetically 'marked'strains of Escherichia coli, Clostridium perfringens or Bacillus thuringiensis on slaughter instruments before use and examining deep tissue samples for their presence post mortem . Bacteria present on the captive bolt pistol were recovered from the spleens of beef cattle and those placed on the pithing rod were found in both spleen and muscle of the flank and neck. Bacteria from the throat cutting ('stick') knife were isolated, on different occasions, from the heart, lung, spleen, liver and kidneys of sheep though rarely from their muscles. Orally administered bacteria were found in the spleen and lung, but not the musculature, of pigs.     

Functions of Invertebrate Hemoglobins with Special Reference to Adaptations to Environmental Hypoxia

The oxygen-binding properties and some associated structuralfeatures of invertebrate hemoglobins (Hb) are reviewed togetherwith the environmental conditions (particularly in stressfulhabitats) that influence oxygen-binding functions in nature.Compared to the vertebrates invertebrate Hbs display a spectacularvariation in functional properties, which is manifest withinthe major systematic groups of animals and within the differenthistological and molecular categories of the pigment. This variabilityis seen primarily to represent adaptations to the wide rangeof environmental conditions to which Hb-bearing invertebratesare subjected in nature but also to reflect certain organismicfunctions, which determine the internal conditions under whichthe Hbs work in life. These adaptations appear to be uniquelydirected towards optimizing the transfer of oxygen from theenvironmental source to the mitochondrial combustion sites.The immense structural and functional complexity of invertebrateHb systems may well compensate for a decreased organizationat the organ level compared to that in vertebrates shiftingmore of the regulatory burden to the molecular level.