Figure 12. — Testing an early model evis- 

 cerator similar to units now in com- 

 mercial operation. 



some variation of a heat-shock method. The 

 principle is not new and is used in other seg- 

 ments of the food processing industry. Heat, 

 usually hot water, provides a blanching effect 

 and mechanical shock frees the whole animal 

 from the shell prior to evisceration. The meat 

 should not be overheated so that it remains a 

 "fresh" product. In calico scallop the top shell 

 is commonly heavily encrusted with barnacles 

 which insulate that shell. Thus, in providing 

 adequate heat to the top shell, the bottom one 

 is likely to be overheated. The viscera, how- 

 ever, insulates the adductor muscle, and by 

 subjecting scallops to mechanical shock both 

 before and after a brief period of heat, shuck- 

 ing is satisfactorily effected. It is much more 

 difficult to shuck live scallops than dead iced 

 scallops because the adductor muscle of live 

 animals is more firmly attached to the shell. 



The shore-based shucking operation is there- 

 fore easier but with added quality problems. 

 The proper combination of heat and mechanical 

 shock works well with live scallops at sea. 



Although more experience has been gained 

 from heat shock, other methods have been tried. 

 A method for shucking scallops electronically 

 was described by Carpenter (1963), but the 

 cost was prohibitive and it was not attempted 

 commercially. It has been reported that the 

 adductor muscle of live scallops placed in sea- 

 water and subjected to low voltage direct cur- 

 rent contracts sufficiently free from the shell 

 to effect shucking. Other developments concern 

 the use of live steam (Meyer, 1969) and gas 

 flame (Matzer, 1965) for heat. 



The most successful heat shock shucker is 

 shown in figures 13, 14, and 15, and its opera- 

 tion may be described as follows : 



13 



