ANISAKID PARASITES, STAPHYLOCOCCUS-AUREUS AND BACILLUS-CEREUS IN SUSHI AND SASHIMI FROM SEATTLE AREA RESTAURANTS

Samples of salmon, tuna, mackerel, and rockfish sushi were analyzed fo r parasites from 32 of the approximately 50 restaurants in the Seattle area that prepare sushi. The restaurants were sampled up to three tim es over a 19-month period. Some specialty grocery stores providing res taurants and consumers with sashimi were also sampled. Salmon sushi wa s most commonly affected with almost 10% of pieces infected with a max imum of 3 nematodes per piece. Only single infections were present in mackerel sushi with frequency of 5%; and tuna and rockfish sushi were free of nematodes. All nematodes were third-stage juveniles of the gen us Anisakis. Except for two moribund nematodes, all juveniles from sus hi were dead, most likely the result of the practice of using fish tha t have been previously frozen. The two moribund nematodes were present in one salmon sushi sample, indicating that incompletely frozen produ ct had been used. For the sashimi, no parasites were found in tuna; ho wever, a live anisakid was found in one collection of rockfish sashimi . Efforts to detect anisakid nematodes with nondestructive methods wer e generally unsuccessful. Neither inspection per ultraviolet light nor by candling was effective for salmon sushi. Candling was also ineffec tive for mackerel but was useful for rockfish and appears to be approp riate for the analysis of tuna sushi. Results of analyses of rice from sushi samples from 19 of the restaurants indicated that the pH levels were at 4.6 or below, and no fecal coliforms were detected. Most of t he aerobic plate counts were below log 6, with only 2 between log 6 an d log 7. Bacillus cereus and Staphylococcus aureus were detected in ri ce from six restaurants each, but in no samples were these two organis ms found together, and levels were well below those of public health i mportance.