Bacteria standards of merluccius capensis / paradoxus (Cape Hake) and other deepsea whitefish products

Abstract

This study analysed the bacteria numbers of Hake products manufactured at 6 different levels of processing complexity, analyses were conducted at 20°C on Salt Water Agar (SWA) for a 48h incubation period. This enumeration method was suitable for indicating time and temperature related abuse in the processing system. This method was sensitive in indicating the level of processing complexity. The aerobic bacteria enumerations at 20°C (SWA) were compared to the current EU/FDA (European Union/Federal Drug Administration USA) standard procedure testing samples on Plate Count Agar, (PCA) incubated at 30 - 35°C. The method using SWA incubated at 20°C provided better and more accurate bacterial counts under "good" and "poor" manufacturing practice. The hurdle concept was applied, using gamma irradiation, temperature (Time), chemical preservatives and Vacuum packaging in an attempt to prolong the shelf life of fresh, uncooked Cape hake and Kingklip products. Radurization was effective only when the treated product was kept at refrigerated temperatures. Temperature was the most important control measure in extending the shelf life of the products. No shelf life extension was achieved with the use of chemical preservatives. Vacuum packaging was not effective in prolonging shelf life of the products and did not show any benefit when compared to oxygen permeable vacuum (microaerophilic) packaging. Determination of the total aerobic viable bacteria numbers at 20°C SWA, were suitable for estimating the shelflife of deepsea whitefish products.