Crop Process Engineering

Lesson 11. Poultry Meat and Egg Processing

Transportation of birds: During loading, unloading and transport, care should be taken that birds should not injured and stressed. Over loading must be avoided. Also, plastic crates having sufficient openings are to be used for transportation. The crates must be easily cleanable, disinfest and durable. The birds must be transported in the morning hours.

 1. Poultry Meat Processing  

The unit should be constructed with adequate infrastructure facilities like good lighting, proper ventilation, adequate potable water and proper drainage system for hygienic processing of chicken meat. Separate space must be provided for handling meat and other edible offal whereas separate area to be provided for unclean operations such scalding,    de-feathering and evisceration to handle inedible parts of the slaughtered birds. Sufficient facilities are to be provided for chilling/storing the carcasses. The walls and floor must be easily cleanable in nature.

 Hygienic slaughter of birds

Birds must be fasted for 12 hours prior to slaughter, but provide adlibidum water, which facilitates to minimize the microbial load in the intestine of the birds to reduce the risk of contamination during evisceration.

 Stunning:Hang the birds for slaughter in such a way for easy stunning. By stunning the birds, maximum blood can be removed from the carcass which helps in extending the shelf life of the meat.

 Bleeding : Immediately after stunning, the birds must be stuck with a sharp knife by serving the major blood vessel sin the neck. Allow 2-3 minutes for bleeding. Provide bleeding cones for hygienic and aesthetic removal of blood.

 De-feathering :De-skinning is one of the methods and more safe method of removing the feather as the chances of microbial contamination is less in this method. But, commonly the slaughtered birds are scaled by dipping in hot water of 50-60^oC which loosens the feather and by hand picking the feathers will be removed. Scalding tanks as well as de-feathering machines are available for removal of feathers in a more hygienic way.

 Evisceration :Eviscerate the carcass as quick as possible by removing the anal gland followed by opening the abdomen next to the keel bone and remove the visceral organs and collect the edible and inedible offal separately for easily processing and delivery.

Washing of carcass :After evisceration, the carcass is looked for any change in color, or / and abnormality and the carcass without any deviation is allowed for further processing. Remove the neck. Wash the carcass thoroughly with potable water.

Storage:In most of the days the meat will be sold immediately. If it doesn't happen chilling the carcass to 4^oC in a chiller/refrigerator. In case of small processors keep the meat in the insulated boxes with ice.

 2. Egg Processing

Egg has a shell made of calcium carbonate which is white or brown in colour. Eggs contain two parts albumen white part (56-61 per cent) and yellow part yolk (27.30 per cent). Egg contains 12-14 per cent proteins, with all the essential amino acids. Egg yolk is an excellent source of vitamin A and D. Egg is also good source of vitamin B. Egg contains 1 per cent minerals like iron (present in yolk), calcium, phosphorus and sulphur.

 Egg drying :Egg powder is prepared by drying the egg. Egg powder may be reconstituted before use by mixing in desired quantity of water. The white, yolk or whole egg after pasteurization may be dried with the help of different methods of drying. Spray drying method is commonly used for drying the eggs. The pasteurized liquid egg is forced through a high pressure nozzles or through atomizer to form an spray in drying chamber. Hot air is fed to chamber for drying. The powdered egg is cooled and packed in suitable packaging material.    

 Egg freezing :Egg may be preserved by freezing. In freezing egg cannot be frozen in the shell since the egg shell would crack with the expansion of liquids when frozen. Therefore, the whole of the egg liquid content is frozen or it is separated into white and yolk and then frozen. In freezing of eggs, to reduce contamination i.e. the control of microorganisms is important. So, to reduce the contamination, the shells are generally washed just before egg shell is broken and then freezing is done quickly as possible. The whole egg or yolk is pasteurized at 60-61.5⁰C for 3.5 to 4 min. without changes in physical and functional properties. Egg white is very sensitive to heat and easily coagulated near the pasteurization temperature. Pasteurized whole or separated eggs are placed in suitable container and frozen in sharp freezer room with circulating air at -29 ⁰C. The freezing process may be completed in 48-72 hours.