Occurrence of toxigenic Staphylococcus aureus in ready-to-eat food in Korea.
Toxigenic Staphylococcus aureus contamination in ready-to-eat (RTE) food is a leading cause of foodborne illness in Korea. To monitor food contamination by S. aureus, a total of 3332 RTE food samples were selected from nationwide wholesale marts between 2003 and 2004 and examined. A total of 285 (8.6%) of the overall samples were contaminated by S. aureus. According to the analysis, 31.6% of the tested cream-cakes, 19.8% of the raw fish, and 19.3% of the rice cakes with filling were contaminated with S. aureus. Forty-seven percent of the strains isolated from the contaminated food were enterotoxigenic S. aureus. The phenotypic result of the strain isolated from food showed that 48% of the strains produced one or more toxins, such as staphylococcal enterotoxins A, B, and C (SEA, SEB, and SEC). At least one SEA was produced by over 90% of the toxigenic strains. Other toxins, such as SEB, SEC, SED, SEA+SEC, and SEC+SED, were each detected. Toxic shock syndrome toxin 1 (TSST-1), a causative agent of toxic shock syndrome, was detected in 13 strains of the toxigenic isolates from the food. As the result of genotyping, 22 strains with a toxin gene that was not detected in the phenotypic analysis were also detected. Sixty-nine percent of the toxigenic strains had at least one sea gene, and the most prevalent genotype was sea+seh (34.4%), followed by sea (18.8%) and sea+seg+sei (15.6%). The tst gene encoding TSST-1 was found in 13 strains (13.5%). The genes (eta and etb) encoding exfoliative toxins A and B were not detected in any of the samples.
Oh
Su Kyung
SK
Food Safety Research Division, Korea Food Research Institute, Songnam, Kyunggi-do, 463-746, Korea.
Lee
Nari
N
Cho
Young Sun
YS
Shin
Dong-Bin
DB
Choi
Soon Young
SY
Koo
Minseon
M
D001939:Bread / Q000382:microbiology; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004768:Enterotoxins / Q000378:metabolism*; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D005838:Genotype; D006801:Humans; D007723:Korea; D008461:Meat Products / Q000382:microbiology; D015995:Prevalence; D017747:Seafood / Q000382:microbiology; D013211:Staphylococcus aureus / Q000254:growth & development* / Q000302:isolation & purification / Q000378:metabolism
D004768:Enterotoxins; C026066:enterotoxin A, Staphylococcal; C031818:enterotoxin B, staphylococcal; C034959:enterotoxin C, staphylococcal