Effects of a liquid potassium diformate blend as preservative for Sardines Sardinella sp. under tropical conditions

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1 Effects of a liquid potassium diformate blend as preservative for Sardines Sardinella sp. under tropical conditions Christian Lückstädt and Kai-J. Kühlmann ADDCON

2 Importance of fish meal Aquaculture growth rate of 9% per annum for the 10 years to 2002; slightly less afterwards Fishmeal is produced mainly from sustainably managed stocks; about 20-25% comes from slaughter waste Increasing demand for fresh, high quality fish meal especially for the salmon and shrimp aquaculture, as well as for other high-quality animal feeds Source:

3 Fresh, high quality fish meal Indicator: Total volatile nitrogen (TVN) TVN is used as a criterion for freshness in fish raw material (Haaland and Njaa, 1988) TVN consists of trimethylamine and ammonia Its amount increases with time of storage in the unfrozen state therefore reducing the quality of the fish meal (lower protein quality - inferior amino acid profile, increased biogenic amines)

4 Scenario of industrial fish storage Temperature? Dosage of Storage period preservative Quality of raw material

5 Industry targets TVN levels may reach around 70 mg / 100 g in wet stored cooled (5-7 ºC) fish, without preservatives after only 2 days The industry considers TVN levels in fish meal below mg / 100 g as good quality! Preservatives based on organic acids or acid salts can solve the problem!

6 Fish preservative applications Temperate versus Tropical conditions Europe Moderate climate with Low temperatures Low humidity Low concentrations of preservatives are sufficient to prolong freshness of caught fish Fish Preservative SE Asia Tropical climate with High temperatures High humidity Direct contact immediately after the catch Higher concentrations of preservatives are necessary

7 Acid-salt blend Consists of: Potassium diformate (KDF) Formic acid Antioxidant / Corrosion inhibitor Chemical structure of potassium di-formate

8 Antimicrobial effect of acids destruction of microorganisms Organic acids inhibit bacteria growth thereby preventing degradation of the fish meal

9 Usage of acid-based preservatives Acid-blends can be used for all species of industrial fish and all types of by-products: Sardines/Anchovy Blue Whiting Sand Eel Norway Pout Capelin By-products from Red fish White fish Chicken

10 Experimental Design Sardine storage Fish treatment* Sardines treated with KDF Non-treated Sardines Acid blend** [%] Temperature [ C] Storage time*** [h] , 48 and , 48 and 72 *Sardines trawled in the Gulf of Thailand **Acid blend: KDF (Fishform Plus) ***Measurement of Dry matter (DM), Total volatile nitrogen (TVN) and histamine levels, (n=3)

11 Experimental Results Dry matter a b Values with a different superscript differ significantly at P<0.05

12 Experimental Results - TVN Preservative / storage time 0.0 % KDF (n = 3) 0.4% KDF (n=3) 24 h 48 h 72 h 26.0±1.2 a 59.4±1.1 b 52.4±0.4 b 25.2±0.5 a 30.2±0.5 a 37.5±5.5 a Values with a different superscript differ significantly at P<0.05

13 Experimental Results Biogenic amines Levels of histamine were measured after 48 h of storage

14 Experimental Results - Remarks Economic analysis: Surplus of 3% in dry matter content Higher quantity in fishmeal production Additionally, higher fishmeal quality is being achieved (lower TVN-values of up to 50%) Fishmeal can be stored longer without losses due to lower moisture content and inhibited bacterial growth Feed/food safety is achieved by lowering biogenic amines level (histamine) by nearly 66%

15 Conclusion Fishmeal preservatives are crucial for expanding fishmeal industry Preservatives based mainly on potassium diformate and formic acid keep the quality of industrial fish (optimum TVN-levels) Acid blend was independently proven and granted the EU-approval Organic acids in fishmeal furthermore have as a positive effect on the performance of treated fish (Christiansen & Lückstädt, WAS 2008)

16 Thank you for your attention!