In most fish canneries offal from the preparatory processes are available for manufacturing by-products. In general the main by-products are canned and frozen pet food, minced frozen fish and fish silage for animal feeding and fish meal. oil can be recovered from the canning process however this should only be used for industrial purposes.
Quality of the by-products depends on the freshness of raw material, and their fat content and nutritional value. Fish flesh is generally more valued than viscera, heads, and backbones.
The source and approximate yields of by-products from various fish canning operations are shown in Table 16.
Table 16 Source and approximate yields of by-products from various fish canning operations
By-product |
By-product yield from canning operations |
||
Tuna (%) |
Sardine (%) |
Salmon (%) |
|
| Pet food | 4-6 |
- |
- |
| Fish meal | 30-35 |
20-30 |
30-35 |
| Industrial oil | <5 |
5 |
- |
