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United States Department of Agriculture

Agricultural Research Service

Title: Stabilizing Fish Byproducts through Modified Silage Processes

item Bower, Cynthia
item Hietala, Katie
item Delaca, Theodore

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/11/2008
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Fish byproducts, (such as heads, viscera, and frames) can create disposal issues for processors in Alaska. The most common method of preservation for these high-protein byproducts is through production of fish meal. However, less energy-intensive forms of stabilization exist. Acidification through lactic acid bacteria (LAB) fermentation is a relatively simple process for stabilizing fish, although a source of fermentable carbohydrate must be added. More than 18 million lbs of potatoes were grown in Alaska in 2006, with an estimated 20% loss. This agricultural waste was evaluated as a source of fermentable carbohydrate for preservation of pink salmon (Oncorhynchus gorbuscha) through LAB fermentation. A cocktail of homofermentative LAB successfully grew in ground potato pulp without any additional nutrients, while sustaining a pH of 3.7 for 8 weeks. When LAB were added to a 1:1 mixture of potato and ground salmon heads, the pH dropped from 6.5 to 5.7 within 24 hours, but steadily increased to pH 6.5 over 8-weeks. Increasing the potato content of the potato:salmon mixture to 7:3 decreased the pH to 4.9 and remained steady for 10 weeks. Mixtures containing lower amounts of potato did not decrease the pH to an adequate level of acidity to inhibit spoilage bacteria. Discarded agricultural products such as potatoes are a convenient source of fermentable carbohydrate for preservation of fish by-products. These fermented fish products could serve as inexpensive feed sources for agricultural animals, supplements in aquaculture feeds, or as a local compost source for vegetable gardening or energy production.

Last Modified: 06/27/2017
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