Sensory, chemical, and microbiological analyses were carried out on sardines during 18 d of storage in ice. Sensory results indicate that the sardines used in this experiment had a shelf life of 9 d. The pH and dimethylamine (DMA) were found to be useless in determining the degree of sardine deterioration, while trimethylamine (TMA) and total volatile bases (TVB) were accurate in predicting the spoilage process. Histamine production was slowed by refrigeration in ice (2–4°C). The amounts of histamine in flesh at the time of rejection (12th day of storage) were 11.7 and 16.2 mg/100 g of flesh, respectively, with the colorimetric method and the fluorimetric method. At the end of the experiment (highly spoiled sardines), the critical value of histamine (20 mg/100 g) was not reached. However, at the 12th d of storage, the count of all microflora studied was above the limit of 106 CFU/g of flesh.

The results obtained showed that the lactic acid Streptococci and the Leuconostoc are the main groups responsible for the acidification of milk to be transformed into Lben. The most important species were Streptococcus lactis, S. diacetylactis, Leuconostoc lactis and L. cremoris. It was observed that the Lactobacilli were very weakly represented, so they seem not to take any prominent part in the transformation of milk into Lben. Yeasts and Moulds grew regularly, especially when the product became aciâ, but their number never reached a high level in the present study. However they would participa te in the formation of the Lben aroma. Coliforms and fecal Streptococci were present in all the samples.

No abstract

No abstract

Aims: This study investigated the performance of a new chromogenic plating medium for the detection of Listeria monocytogenes from naturally contaminated samples obtained from marine environments in Morocco in comparison with the conventional plating media PALCAM and Oxford. Methods: A total of 479 marine samples (sea water, sediment and mussels) were collected from 16 littoral sites in the region of Agadir (western centre of Morocco). They were examined for the presence of L. monocytogenes using a slight modification of the standardized French method (AFNOR V 08-055) for the detection of L. monocytogenes from food and three different isolation media: PALCAM, Oxford and a new chromogenic plating medium. Results and Significance of the Study: The Oxford and the new chromogenic plating media were found relatively more efficient than the PALCAM medium for the isolation of L. monocytogenes (chi-square test, P < 0AE05) from marine samples. However, the new chromogenic plating medium was significantly more selective for L. monocytogenes (P < 0AE005) than the two other isolation media as 87AE5% of the suspect colonies on this medium were indeed confirmed through identification of the isolates vs 12AE7% for Oxford and only 3AE8% for the PALCAM medium.