The purpose of this study was to investigate the prevalence, toxin gene profiles, and enterotoxin producing ability of Bacillus cereus isolated from environment-friendly vegetables and good agricultural practices (GAP) vegetables. A total of 49 vegetables including 40 environment-friendly vegetables and 9 GAP vegetables were tested. The Vitek 2 system was used to identify B. cereus and the PCR was used to detect 6 toxin genes, respectively. B. cereus was detected in 34 (69.3%) of 49 vegetables and the prevalence of B. cereus in GAP vegetables (44.4%) was lower than in the environment-friendly vegetables (75.0%). The detection rates of entFM, nheA, hblC, and cytK enterotoxin genes, respectively, among all isolates were 100%, 97.0%, 88.2%, and 73.5%, respectively. All of the isolates had at least one or more enterotoxin gene and 20 isolates (58.8%) had hemolysin BL enterotoxin producing ability. The risk of food poisoning from the environment-friendly vegetables and the GAP vegetables has been shown as constant. Thus, it is necessary to expand the supply of GAP vegetables showing lower B. cereus contamination than the environment-friendly vegetables. The characteristics of the environment-friendly vegetables and the GAP vegetables that must be consumed after cleaning should be disseminated to consumers regarding food poisoning prevention.
The purpose of this study was to investigate the microbiological contamination of water and drinking cups in springs and to estimate the toxin gene, enterotoxin production ability and antibiotic susceptibility of foodborne pathogens. Ten spring water and 34 drinking cups were tested. The average number of total aerobic bacteria and coliform bacteria in spring water were 1.8 log CFU/mL and 1.2 log CFU/mL, and in drinking cups were 4.7 log CFU/ 100 cm2 and 1.7 log CFU/100 cm2. Salmonella spp., Staphylococcus aureus, E. coli O157:H7, Listeria monocytogenes, Vibrio parahaemolyticus, Yersinia enterocolitica were not isolated from all of samples but Bacillus cereus was detected in 5 (14.7%) of 34 drinking cups. The nheA and entFM genes were major enterotoxin genes in B. cereus isolated from drinking cups. All of B. cereus tested in this study produce non-heamolytic enterotoxin but only 2 isolates possessed heamolysin BL enterotoxin producing ability. B. cereus was resistant to β-lactam antibiotics. These results revealed that the sanitary conditions of drinking cups in spring should be improved promptly. The substitution carrying a personal drinking cup for the public drinking cups equipped in springs is suggested to prevent food-borne illness.
어린이집 유아들이 공용으로 사용하는 수건의 미생물 오염도와 분리된 식중독 미생물의 장독소 유전자 및 장독소 생산 특성을 분석하여 어린이집 유아 사용 수건의 위생 안전성을 확보하고자 어린이가 손 씻은 후 공용으로 사용 하는 수건 22개 (사용 전 7개, 사용 중 15개)를 연구대상으로 하였다. 일반세균수는 평균 6.2 log CFU/100 cm2로 검출되었고 진균수는 평균 4.1 log CFU/100 cm2로 검출되었 으며 대장균군은 사용 전 수건의 경우 7건 중 4건 (57.1%), 사용 중인 수건의 경우 15건 모두에서 (100%) 검출되었 다. 어린이 사용 수건의 미생물 오염도가 높게 나타나 수 건의 위생적인 살균 세탁 및 상대습도가 낮은 곳에 보관하는 등의 보관 방법 개선이 필요한 것으로 판단되었다. Salmonella spp.의 경우 실험에 사용된 모든 수건에서 검출되지 않았으나, Staph. aureus는 22건 중 5건 (22.7%), B. cereus는 11건 (50.0%)에서 검출되어 B. cereus 오염이 가장 심각한 것으로 나타났다. Staph. aureus 장독소 유전 자와 독소 단백질은 모두 불검출 되었으나 분리 동정된 11균주의 B. cereus 장독소 유전자 실험 결과 hblC, hblD, hblA 유전자가 각각 72.7, 72.7, 54.5% 검출되고 nheA, nheB, nheC 유전자가 각각 81.8, 72.7, 54.5% 검출되었으며 cytK, entFM 장독소 유전자는 각각 45.5, 90.0% 검출 되었다. B. cereus 장독소 실험결과 HBL 장독소는 11균주 중 8균주 (72.7%), NHE 장독소는 5균주 (45.5%) 검출되었고 HBL과 NHE 장독소 중 하나 이상을 생산하는 B. cereus 균주는 10균주 (90.9%)로 나타났다. 수건에 오염된 B. cereus 균주의 교차오염에 따른 식중독 위험성이 상존 하는 것으로 나타나 개인별 수건 또는 종이 타올 사용을 고려하여야 할 것으로 판단되었다.