Investigation of the Effect of Storage Temperature on Physicochemical, Microbial and Sensory Properties of Fresh Shrimp (Litopenaeus vannamei)

Shrimp is one of the most important sources of human food in the world. Shrimp is rich in calcium, phosphorus, iron, iodine and protein. Shrimp protein contains all the essential amino acids of the body. Since the temperature and storage time of shrimp after catching has a great impact on its microbial, chemical and sensory quality. This research was conducted in order to evaluate the effect of temperature and storage time on the microbial, chemical and sensory characteristics of shrimp.

In this study, farmed shrimp (Litopenaeus vannamei) stored at +2 and -2 ° C after catching and cooling with sanitary water. Then, chemical (pH, total volatile nitrogen and peroxide value), microbial (Mesophilic bacteria, cryophilic bacteria, Enterobacteriaceae, Staphylococcus aureus) and sensory characteristics (appearance and texture of meat, odor and eyes) of the shrimps were measured at different times (0, 3, 5 and 7 days).  

The results showed that the rate of chemical and microbial changes in shrimp kept at -2 ° C were significantly lower than the samples kept at +2 ° C (P<0/05). Meanwhile, chemical and microbial changes increased over time. Samples stored at -2 ° C, had the shelf life for one week in terms of pH, total volatile nitrogen, and peroxide value. But the shelf life of the samples at +2 ° C was a maximum of three days. Mesophilic bacteria, cryophilic bacteria, Enterobacteriaceae, Staphylococcus aureus were present in all samples. However, their number at -2 ° C was on average 1.5 to 2 logarithms less than those stored at +2 ° C. In the sensory section, the results showed that shrimps stored at -2 ° C, maintained their quality for up to seven days, while samples stored at +2 ° C had a good score for up to three days and the longer time had drastically reduced their sensory quality.

The results showed that the best storage temperature for shrimp is -2 degrees Celsius and below because at this temperature, in addition to maintaining the sensory and physicochemical quality of shrimps, their shelf life also increases up to seven days.