This study investigated influences of cultivation conditions on microbial
profiles of Pacific White Shrimp (Litopenaeus vannamei) from three different
cultivation environments: location, season and cultivation system (sanitation
control farm and semi-natural farm). The first shrimp samples were collected
from a sanitation control farm in Rayong (Eastern Thailand) in January 2011
(S1). Average temperature of water in the ponds was 27.1±0.2 °C with salinity
22.8±2.5 ‰ and pH 8.50±0.16. After harvesting, the samples were immediately
shocked by ice before subjecting to microbiological analysis. Under these
conditions, total plate counts (TPCs) of shrimps were generally below 4.00 Log
CFU/g. Vibrio spp. was observed in 25 g of all samples. Vibrio parahaemolyticus
was observed in terms of most probable number (MPN) values ranging
from 3.6 to 11 MPN/g. The second shrimp samples were collected from the
same farm in June 2011 (S2). Average temperature and salinity of waters were
significantly higher than S1 (30.6±2.1°C and 30.4±0.4 ‰, respectively), whereas
pH value was not significantly different (8.37±0.17). The TPCs and occurrence
of Vibrio spp. of this batch were also similar to S1, whereas MPN values of V.
parahaemolyticus were significantly higher (240 to >1100 MPN/g). The third
shrimp samples were collected from a semi-natural farm in Samut Songkram
(Central Thailand) in August 2011 (S3). In this farm, salinity was dramatically
lower than the sanitation control farms (0.6±0.5 ‰), whereas the temperature
and pH value were relatively similar (29.1±0.3°C and 8.27±0.27, respectively).
TPCs observed were significantly higher than the control system farms (5.14 to
5.86 Log CFU/g). Vibrio spp. was detected in all samples. Interestingly, MPN