Development of prediction models to estimate the total number of mesophilic aerobic and lactic acid bacteria of squid rings that were cooked before marinating

Abstract

This study was conducted in order to develop different statistical models for estimating the bacterial count of squid rings marinated with lemon juice and mineral water after cooking. The marination ratios and times were as follows: (10:90; 90:10; 50:50; 100:100/100 g squid ring) and (1, 3, 6, 12, 24, 48 and 72 h), respectively. The effects of marination ratios and times on the microbiological and sensory changes of the cooked squid rings were observed at 4°C. Pathogenic bacteria (Vibrio spp., Staphylococcus aureus and Escherichia coli) were not found in the cooked (C) and cooked marinated (CM) squid rings in the present study. The TMC (total mesophilic aerobic bacteria counts) of all groups were determined as consumable at 72 h, whereas the TMC of C and CM samples (C7, CM7, CM14, CM21, CM28) increased to 5.92, 5.83, 5.71, 5.57 and 5.42 log cfu/g, respectively. Regression models were created to estimate the TMC and lactic acid bacteria count (LBC) of cooked squid rings during the marination process at 4°C to determine the increasing rates of bacterial growth of samples. As a result of this study; when compared with Model I and Model II; both of them can be preferred for predicting the TMC of C and CM samples. The variability in the TMC of C and CM squid samples was obtained as 93% in Model I, whereas the variability in the TMC of these samples was observed as 91% in Model II. So, these two models performed well, and they can be used for predicting the TMC of C and CM samples. Additionally, Model III was also developed for estimating the prediction value of LBC of cooked squid samples during the marination process at 4°C. This model was also determined very good performance (86%) to estimate the predicting values of LBC and it can be very essential together used with Model I or Model II for marinated fishery products to estimate the real shelf-life.