Miscellaneous Undesirable Changes Caused by Microbes in Meat

MISCELLANEOUS UNDESIRABLE CHANGES CAUSED BY MICROBES IN MEAT

Spoilage due to bacteria

Bone taint

  • Bone taint is that spoilage that takes place in the deep musculature of carcasses that are heavy, well endowed with fat and also cooled very slowly, and putrefactive bacteria, of anaerobic spore forming type is responsible for this condition
  • The most commonly affected joint is hip joint and putrefaction is evident both in the femur and its surrounding musculature.
  • Stress at slaughter predisposes those animals to this condition.
  • Taint in hams are also encountered and Clostridium putrifaciens andCl. putrificum are the most common bacteria incriminated
  • Rapid cooling can prevent these conditions.

Phosphorescence

  • Phosphorescence is a condition caused by Pseudomonas phosphorescens , in which meat contaminated in the cold stores, which became originally contaminated by sea fishes stored therein ( organism is found in the sea water) shows luminous areas scattered over the surface of carcasses and it appears as though stars were studded on them.

Miscellaneous colour changes on meat surfaces caused by bacteria

  • Serratia marccescens – Red colour similar to beet root juice
  • Pseudomonas cyanagenus- Blue colour
  • Pseudomonas cutirubra – Red mould on charque.

Spoilage due to yeast and moulds

Black Spot

  • A condition caused by Cladosporium herbarum in which black spots appear on carcass surfaces stored above -8 ⁰ C.
    Rhizopus and Pullaria may also be involoved.
  • This is not a mere surface phenomenon and may extend into the muscle even necessitating condemnation of entire quarters

White spot

  • A condition caused by Sporotrichum and Chrysosporium in which white woolly spots appear on carcass surfaces stored above -8 ⁰ C and plentifully at -2.5 ⁰ C and profuse if above 0 ⁰ C.
    This is an entirely superficial condition.

Whiskers

  • Whiskers is a condition caused by Thamnidium and Mucor and their hyphae project about 2.5 cm beyond the surface of meat. They cease to grow at temperatures below -7.5 ⁰ C, but retain viability and proliferate, if exposed above freezing point. Hence whiskers is an indication of temperature abuse.
  • Bluish green moulds such as Penicillium spp also cause surface discolouration in meat which is also superficial.
Last modified: Wednesday, 11 April 2012, 8:14 AM