Histamine fish poisoning is a significant cause of food borne disease related to fish consumption. Photobacterium damselae are strong histamine producers, recently, it considered as an emerging, food borne pathogen of marine fish with a notable increase worldwide. So, a total of 20 fish samples (6 mackerel and 14 sardines) and 50 canned tuna were collected from different supermarkets and retail stores in Giza Governorate.The overall occurrence of histamineproducing bacteria (HPB) by plating the fish homogenates on modified Niven agar plates was 34.3%, the highest percentage was recorded in fresh sardine (85.7%), while the lowest one was detected in canned tuna (14%). The screening of the suspected colonies with PCR assay for the histidine decarboxylase encoding genes (hdc) evidenced that only 25% of fresh sardine HPB isolates were positive. Using of thiosulfate-citrate-bile salts agar (TCBS), evidenced that out of 70 fish homogenates, only 18 (6 mackerel and 12 sardines) isolates were identified as Photobacterium spp. The identification of these isolates using API 20NE evidenced that only 2 isolates obtained from fresh sardine isolates were Photobacterium damselae as well as
harbored hdc gene. These results identify fresh sardine as a potential source of HPB, especially Photobacterium damselae. Therefore, proper handling of fish is mandatory in order to prevent this potentially serious public health threat.