51A-24

K. WALISZEWSKI, Unidad de Investigacion y Desarrollo en Alimentos, Instituto Tecnologico de Veracruz, M.A. de Quevedo 2779, Veracruz, 91700, Mexico

Tilapia shelf life by storage in crushed ice at -1°C with some additives

K.Waliszewski and V.Hernandez

Instituto Tecnologico de Veracruz Departamento de Ingenieria Quimica y Bioquimica A.P. 1380 Veracruz, Ver., 91700 Mexico e-mail kw@itver.edu.mx

Justification The extension of fish shelf life by chilling is essentially due to the reduction in the growth rate and metabolic activity of spoilage causing microorganisms. From our previous study with tilapia six treatments were found as the most adequate for tilapia storage at - 30 C in crushed ice during 15 days of experiment. To avoid fish texture change during storage, super chilling temperature of - 10 C was recommended for future study for longer period of storage. Objective The purpose of this study was to determine the effect of six treatments of crushed ice with additives on gutted tilapia fish stored at - 10 C during 63 days of experiment. Methods Tilapia fish was gutted and stored in six types of crushed ice treatments at - 10 C with 0.2% of ascorbic acid, 0.15 and 0.2% of citric acid and 0.1, 0.15 and 0.2 % of potassium sorbate during 9 weeks of experiment. Two times per week trimethylamine, hypoxantine, total coliforms and psychotrophic bacteria count change were determined. Results Tilapia could be stored on ice without additives for any longer than 10 days due to hypoxantine over limit concentration. Fish kept on ice with additives could be stored up to 60 days and both trimethylamine, hypoxantine, total coliforms and psychotropic bacteria count no limited tilapia storage time. Maybe longer time tilapia storage was obtained due to high quality fish immediately kept in ice with additives after kill. Significance Use of chemical preservatives in crushed ice in combination with immediately after killing of fish storage can extent almost 6-7 times tilapia refrigerated shelf life.