Spoilage of Egg and Poultry.pptx

Spoilage of Egg and Poultry

1. WELCOME

2. CONTENTS INTRODUCTION CONTAMINATION OF EGG CHANGES NOT CAUSED BY MICROORGANISMS CHANGES NOT CAUSED BY MICROORGANIMS PRESERVATION OG EGG

3. INTRODUCTION Microbial and nonmicrobial spoilage occur in eggs during storage. Untreated eggs lose moisture and weight during storage. The changes appear with breathing out the eggs. The white of the egg becomes thinner and more watery as the egg ages and the yolk membrane becomes weaker. The most predominate spoilage (rot) of shell eggs is caused by Gram-negative motile rods: Pseudomonas, Proteus, Alcaligenes, Aeromonas, and coliforms. Pasteurized egg products at refrigerated temperatures have limited shelf life, unless additional preservatives are used.

4. CONTAMINATION OF EGG Most freshly laid eggs are sterile, at least inside, but the shells soon become contami- nated by fecal matter from the hen, by the cage or nest, by wash water if the eggs are washed, by handling, and perhaps by the material in which the eggs are packed.

5. INCIDENCE OF MICROORANISMS ON SHELL OF THE EGG

6. SPOLAGE OF EGG Some of the defects of eggs are obvious from their general appearance, others are shown by candling with transmitted light, and some show up only in the broken egg. Defects in the Fresh Egg Fresh eggs may exhibit cracks, leaks, loss of bloom or gloss, or stained or dirty spots on the exterior as well as "meat spots" (blood clots), general bloodiness, or translu- cent spots in the yolk when candled. From among these, any breaks in the shell or dirt on the egg will favor spoilage on storage.

7. Changes During Storage The changes that take place in eggs while they are being held or stored may be divided into those due to nonmicrobial causes and those resulting from the growth of microorganisms. CHANGES NOT CAUSED BY MICROORGANISMSCHANGES Untreated eggs lose moisture during storage and hence lose weight. The amount of shrinkage is shown to the candler by the size of the air space or air cell at the blunt endof the egg, a large cell indicating much shrinkage. Of more importance is the change in the physical state of the contents of the egg, as shown by candling or by breaking out the egg.

8. The white of the egg becomes thinner and more watery as the egg ages,and the yolk membrane becomes weaker. The poorer the egg, the more movementthere is of the yolk and the nearer it approaches the shell when the egg is twirled during candling. When an old egg is broken onto a flat dish, the thinness of the white is more evident and the weakness of the yolk membrane permits the yolk to flatten out or even break. CHANGES CAUSED BY THE MICROORGANISMS Take to be accomplished by causal organisms to Cause Spoilage Contaminate the shell Penetrate the pores of the shell to membranes shell must be moist) Grow through shell membrane to reach white. Grow ine ggs white to reach egg yolk. Time taken to penetrate varies with organism and temperature In general more spoilage is caused by bacteria than by molds.

9. Bacteria need to overcome the anti- bacterial properties of albumen to cause Spoilage of eggs Also thy use the protein complexes as a Source of nitrogen for Growth. Bacterial spoilage Chief is called as rots. Three chief one are Green rots,Colourless rots and Black rots. The othe Two are Pink rots and red rots. Bacteria spoilage of Egg

10. GREEN ROTS Green rot It is caused by Pseudomonas fluorescence. Green egg white shows fluorescence when exposed to UV light In later stage of spoilage, egg yolk disintegrates and mask green color of egg white. Odor is lacking or fruity or sweetish.

11. COLOURLESS ROTS It may be caused by Pseudomonas, Acetobacter, Acinatobacter and coliform. It is caused by Proteus and sometimes Pseudomonas and aeromonas Egg yolk blackens and then breakdown to give whole egg content muddy brown Odor is putrified due to H2S BLACK ROTS

12. PINK ROTS 4. Pink rot It is caused by Pseudomonas usually at the later stage of green rot. They are similar to colorless rot except that pink coloration occurs in yolk and white.

13. 5. Red rot Most infrequently occurring one. Caused by a species of serratia. Odour is mild & not offensive. RED ROTS

14. FUNGAL SPOILAGE OF EGG Molds causing spoilage of egg includes Penicillium, Sporotrichum, Mucor, Botrytis, Alternaria, Thamnidium etc. Spoilage of eggs by fungi goes through stages of mold growth. Pin spot molding. Fungal rotting.

15. PIN - SPOT MOLDING In this case, small compact colonies of mold appear on the shell and usually just inside the shel It is the final stage of spoilage by mold. In this case, mycelium of the mold grows through the pores and cracks in the shell Jellying of egg white may occur and colored spots may be produced Hypha of mold grows through the yolk membrane and rupture it, so that yolk mixes with the white. FUNGAL ROTTING

16. PRESERVATION ASEPSIS REMOVAL OF MICROORANISMS USE OF HEAT USE OF LOW TEMPERATURE PRESERVATION BY DRYING USE IF PRESERVATIVES USE OF IRRADIATION

17. CONTENTS