Microbial ecology of different sardine parts stored at different temperatures and the development of prediction models

Abstract

The microbial ecology of sardines stored at 4 and 10 °C was determined using the Application Programming Interface (API) test with a stated statistical accuracy (%) at the species level for lactic acid bacteria, Enterobacteriaceae and Staphylococcus species. The microbial ecology of the gill (a), skin (b), meat (c) and intestine (d) of sardines stored at 4 °C was as follows; (a) Leuconostoc mesenteroides spp. 99.9%, Candida ciferrii 99.9%, Serratia odorifera 97.9%; (b) Enterobacter cloacae 95.6%, Pantoea spp. 62.8%, Pseudomonas luteola 99.7%, Rahnella aquatilis 78.3%; (c) Acinetobacter baumannii/calcoaceticus 98.5%, Pantoea spp. 62.8%, L. mesenteroides spp. 99.9% and (d) L. mesenteroides spp. 99.9%, Aeromonas hydrophila 65.4%. The microbial ecology of gill (e), skin (f), meat (g) and intestine (h) of sardines stored at 10 °C was as follows: (e) Cryptococcus humicola 79.9%, Cryptococcus laurentii 99.4%, Candida guilliermondii 99.8%, Staphylococcus lentus 99.4%; (f) L. mesenteroides spp. 99.9%, Candida ciferri 53.8–87.9%; (g) Pantoea spp. 25.4–70.5%, Morganella morganii 96.6% and (h) C. ciferrii 53.8–87.9%, A. hydrophila/caviae 97.8%, Cronobacter spp. 96.5%. All bacteria counts were mainly observed in the order: intestine > gill > skin > meat, at both storage temperatures. Statistical prediction models were developed to estimate the quality and shelf-life of sardines during storage. The quality of sardines was measured using regression models. The Pearson correlation r between storage times for the quality and shelf-life of gill, meat and intestine was 0.86 for sardines stored at 4 °C (model 1), and was r=1 for storage times for the quality of gill and meat at 4 and 10 °C (model 2).