Aseptic Autolysis of Muscle: Biochemical and Microscopic Modifications Occurring in Rabbit and Lamb Muscle During Aseptic and Anaerobic Storage

Abstract

111 vivo muscle is normally sterile. This tissue becomes highly contaminated post morteni by aerobic and anaerobic flora, however, if it is stored at normal or higher temperature and if it is not protected against contamination from these sources by rather drastic technics. I t has been shown that irradiation can protect muscle from such contamination, but we know that sterilization doses of radiation do not completely inhibit proteolysis (8). We have chosen not to rely on such sterilizations for our first experimentation. W e have preferred, rather, to work under strictly aseptic conditions and to excise the muscle material on which we observe modifications during its normal aseptic autolysis. EXPERIMENTALMatexiale. Lambs (50 kg.) and rabbits (3 kg.) have been used. For practical rcasons, we have limited our observations to the dorsal muscles of animals in good health and more particularly those free from Bang's and other diseases. Excision was done as follows :The animal was first sheared and then thoroughly washed with soap and water. It was epilated with SBa-starch-ZnO mixture on the whole surface of the back and washed again with lukewarm water. It was then slain and bled by severing the throat veins. Thereupon, we laid the animal on an operating table and covered it with sterile towels. The animal, still on the table, was carried into a special room where the atmosphere had been sterilized both by UV rays and Cresol aerosols. (Operators wore sterile blouses, masks and gloves; instruments were heat sterilized). The hide was cut along the spine and turned over revealing a large operating area; this area was bordered by sterile towels. Dorsal muscles thus denuded were excised from the ribs and the apophysis.Working with the lamb, the muscles were cut under UV rays into pieces of approximately 50 gr. ; with rabbits, muscles were stored with no further dissection.To protect OUT muscle samples against oxidation by atmospheric oxygen, we put them in large special sterile test tubes composed of two compartments. In the first compartment, we introduce 10 cc. of fresh alkaline pyrogallol solution (25 g. pyrogallol + 75 cc. H,O + 10 g. NaOH in pellets). In the second one, the muscle sample was introduced immediately after dissection ; the tubes were then hermetically closed with rubber stoppers. The samples were thus protected against evaporation.This method has become routine in our laboratory, and we find that a trained operator can prepare and operate on 5 rabbits per day. For a lamb, we need 3 persons and the operations are somewhat refined with regard to sterile manipulations. Bacteriological controls show that the percentage of contaminated samples excised in this manner is practically nil. However, each sample is tested after storage for the possible presence of aerobic or anaerobic organisms.We find that the presence of pyrogallol enables us to keep unaltered the original color of our samples. But, if pyrogallol is absent, the samples soon lose their pink pigmentation and become light brown-probably through th...

Aseptic autolysis in rabbit and bovine muscle during storage at 37°

“…14, July Flamed samples from adrenaline treated rabbits K I5 ( I ) 6.82, (2) 6.64 Food Agric., 1963, Vol.…”

The effect of ageing on the sensory and chemical properties of boiled beef aroma

“…At ageing temperatures, slow naturally occurring enzyme activity occurs in meat and this decreases with ageing time. 5 Proteases produce an increase in free amino acids, principally alanine, glutamic acid, leucine and cystine-liberated from the sarcoplasniic proteins. The importance of amino acids as beef aroma precursors is well established, both per se6 and in conjunction with other compounds, e.g., in Strecker degradations and Maillard reacti0ns.l-3 Lipolytic enzymes also operate and during ageing there is an increase in free fatty acid concentration.7~ 8 Fatty acids, particularly the cl8 unsaturated acids are precursors of carbonyl comp0unds.9-~~ Such compounds have been implicated in meat flavour, particularly fat flavourlz and roasted flavour13 and total carbonyl concentration increases in beef muscle during ageing.l* Other reactions relevant to flavour production which occur during conditioning include the breakdown of adenosine triphosphate forming inosine, hypoxanthine and ribose, which when heated in the presence of various amino acids give rise to meaty o d o~r s .~, 15, l 6 The Strecker degradation of amino acids is catalysed by inosinic acid.17 However, Rhodes has found no correlation between nucleotide degradation and flavour changel8 while Lyaskovskaya and Safronova also concluded that hypoxanthine does not participate in the development of meat aroma.19 An increase in concentration of the soluble carbohydrate intermediates of glycolysis also occurs on ageing and some glycogen is converted into glucose by a-amylase.l5 This, together with the simultaneous production of free amino acids, provides a pool of Maillard reactants.…”

Development of a new technique for obtaining axenic meat

“…Techniques available at the present time for obtaining axenic meat are based either on a superficial decontamination by means of alcohol (Sharpe, 1963) or antibiotics (Van den Berg, 1964) aseptic sampling in a special surgical room (Zender et al, 1958) in a laminar air flow (Buckley et al, 1976) or by application of a surgical isolator procedure (Ockerman et al., 1964;Brassine and Dubois, 1975). The major disadvantages of these techniques are insufficient decontamination with alcohol (Sharpe, 1963), impossibility in obtaining growth of inoculated bacterial strains after utilization of antibiotics ( Van den Berg, 1964) or the high costs involved in techniques using surgical isQlators (Ockerman et al, 1964;Brassine and Dubois, 1975).…”