Enterococcus species are considered as parts of the indicator strains for fecal contamination on retail meats because they reside in the gastrointestinal tracts of humans and animals. Frequent acquisition and dissemination of antibiotic resistance genes among enterococci have increased their morbidity and mortality rates and thus become a serious public health issue. For example, vancomycin (Van)-resistant and/or multidrug resistant (MDR) enterococci are increased during recent years. Currently, only a few therapeutic options have been approved for linezolid (LZD), daptomycin (DAP), and tigecycline (TGC) to treat VAN-resistant and/or MDR enterococcal infections. In this review, we have updated the recent status of enterococcal resistance to those three last-resort antimicrobials (LZD, DAP, TGC) among livestock animals and retail meats.

Antimicrobials in human medicine are classified by The World Health Organization (WHO) into three groups: critically important antimicrobials (CIA), highly important antimicrobials (HIA), and important antimicrobials (IA). CIA are antibiotic classes that satisfy two main criteria: that they are the sole or the only available limited therapeutic option to effectively treat severe bacterial infections in humans (Criterion 1), and infections where bacteria are transmitted to humans from non-human sources or have the potential to acquire resistance genes from non-human sources (Criterion 2). WHO emphasizes the need for cautious and responsible use of the CIA to mitigate risk and safeguard human health. Specific antimicrobials within the CIA with a high priority for management are reclassified as “highest priority critically important antimicrobials (HP-CIA)” and include the 3rd generation of cephalosporins and the next generation of macrolides, quinolones, glycopeptides, and polymyxins. The CIA list is the scientific basis for risk assessment and risk management policies that warrant using antimicrobials to reduce antimicrobial resistance in several countries. In addition, the CIA list ensures food safety in the food industry, including for the popular food chain companies McDonald's and KFC. The continuous update of the CIA list reflects the advancement in research and emerging future challenges. Thus, active and deliberate evaluation of antimicrobial resistance and the construction of a list that reflects the specific circumstances of a country are essential to safeguarding food security.

살균제 저항성 Bacillus cereus 분리주의 포자에 살균제와 열을 가해 그 병합효과를 비교하였다. 사용된 B. cereus 균주는 차아염소계 처리 후 분리한 균주(S-BC-50, S-BC-52), 과산화수소 처리 후 분리한 균주(S-BC-23, S-BC-48), acetic acid 처리 후 분리한 균주(S-BC-54, S-BC-56)와 표준균주 B. cereus KCTC1661을 사용하였다. B. cereus 분리주의 포자를 다음 조건으로 처리하였다; i) 0.56% 과산화수소수(HP), ii) 3% acetic acid(AA), iii) 80oC 열처리(H80), iv) 90o 열처리(H90), v) HP+H80, vi) HP+H90, vii) AA+H80, viii) AA+H90. 포자를 HP와 AA 처리에 노출시킨 결과 포자가 감소하지 않았지만, H80과 H90 처리에서는 1~2 log CFU/mL가 감소하였다(P<0.05). 병합처리(HP+H80, HP+H90, AA+H80, AA+H90)에 포자를 적용시킨 경우, 포자수가 3-6 log CFU/mL 감소 하였지만, AA+H80과 AA+H90은 AA만 처리했을 때보다 오히려 포자 제어가 감소했다. 따라서 HP와 열처리를 병합했을 때는 B. cereus 포자를 불활성화하기에 효과적이지만, AA의 경우 B. cereus 포자가 열처리에 대한 저항성을 증가시키는 것으로 사료된다.

The purpose of this study is to evaluate antimicrobial effects of organic acid and some natural occurring antimicrobials against Staphylococcus aureus isolated from various origins (vegetables, peanut, pea leaf, kim- bab, person, perilla leaf, and animal) and to calculate their MIC and MBC values. Five organic acids (acetic, lactic, citric, malic, and propionic acid), three essential oils (carvacrol, thymol, and eugenol), and two other natural antimicrobials (nisin and cinnamic acid) were evaluated for their antimicrobial effects against 113 strains of S. aureus using combination treatments. Propionic acid (7%), nisin (1%), thymol (1%), carvacrol (1%) showed antimicrobial activities against S. aureus strains in agar disc diffusion test. And, carvacrol, thymol, and nisin were found to be the most effective with the lowest MIC values of 0.0313%, 0.0625%, and 0.0625% against S.aureus, respectively. Propionic acid (0.2313%) and citric acid (0.6000%) were the most effective among organic acids tested. Therefore, these five antimicrobials were selected for next combination treatments. Combination of propionic acid and citric acid were showed the strongest inhibitory effectiveness against S. aureus among combination treatments. These results suggest that organic acid such as propionic and citric acid, and natural occurring antimicrobial such as nisin, carvacrol, and thymol might be possibly used as preservatives for inhibiting S. aureus in foods.

We investigated eight active natural antimicrobials for preservation of functional beverages that are usually degraded by yeasts rather than by bacteria due to a high sugar content and a low pH. Five strains of yeasts (S. cerevisiae, Z. bailii, P. membranaefaciens, C. albicans, and P. Anomala) were tested with eight natural antimicrobial agents (ε-polylysine, yucca extract, vitamin B1 derivative, scutellaria baicalensis extract, chitooligosaccharid, allyl isothiocyanate, sucrose-fatty acid ester, and oligosaccharide). The lowest minimal inhibitory concentrations (MIC) were 10 ppm for oligosaccharide and sucrose-fatty acid ester against S. cerevisiae and Z. bailii, 10 ppm for allyl isothiocynate against P. membranaefaciens and C. albican, and 10 ppm for allyl isothiocynate and oligosaccharide against P. anomala . No growth were observed for five kinds of yeasts in functional beverages containing sodium benzonate at concentration of 0.015% or higher. The resistance of S. cerevisiae, Z. bailii, and P. Anomala against natural antimicrobial agents was lower than those of P. membranaefaciens and C. albican. Allyl isothiocyanate, oligosaccharide, and sucrose- fatty acid ester showed the highest antimicrobial activities among the eight tested antimicrobials. These results can be applied to develop new natural antimicrobial agents to improve microbial quality of functional beverages.

Antifungal activity of seven natural antimicrobials, such as ε-polylysine, extract of Yucca shidigera, TLS (vitamin B1 derivative), BMB-FS, chitooligosaccharide, KDSP 001, and KDSP 002 were investigated for their applications in functional beverage. Five fungi including Aspergillus niger, Penicillium citrinum, Rhizopus oryzae, Fusarium moniliforme, and Mucor rouxii were applied as test fungi and mininum inhibitory concentrations (MICs) of antimicrobials were examined. TLS exhibited the strongst antifungal activity among tested antimicrobials and the growth of all fungi was inibited at 100 ppm. The antifungal activity of BMB-FS appeared different. The growth of Fusarium moniliforme was inhibited by BMB-FS at 100 ppm, but it exhibit antifungal activity on P. citrinum, and M. rouxii at 1000ppm. MICs of TLS appeared to be 60 ppm for four test fungi except A. niger (100 ppm). These results indicate the possible usage of TLS and BMB-FS as natural antimicrobials in functional beverage.

This study was conducted to evaluate the MSPD and HPLC method about simultaneous determination for residual synthetic antimicrobials of sixteen species such as sulfonamide etc. in livestock products. Elution solvent used in HPLC was ethylacetate : acetonitrile (4 :1), and mobile phases for solvent A and B were water : methanol : acetonit rile : phosphric acid (700:250:50:0.2) and 100% acetonitrile respectively. The detector and absorbency used in HPLC was UV 266 nm. This study showed the reduction effect of 99.1% for organic solvents, 94% for experimental steps, 95% for analytical time and manpower and 98.9% for costs compared with korea food standard method. The average recovery rates for chicken, bovine, pork and milk were 67.7% 96.2 %, 67.7%-96.6%, 70.0%-96.2%, and 13.8%-97.8%.

도체표면에서 분리한 E. coli O157;H7 CDF1, A. sobria CDF3, S. aureus CDF2의 성장을 억제하기 위한 방안을 검토하였다. E. coli O157:H7 CDF1와 A. sobria CDF3는 NaCl 4% 이상 농도에서 성장이 억제된 반면 lactic acid 0.1%는 성장에 영향을 미치지 않았다. S. aureus CDF2은 NaCl 농도 4%에 의해 성장이 뚜렷하게 억제되지 않았으나 lactic acid 0

경제적이면서 효과적인 항균성 필름의 생산방법으로서 corona 저려한 저밀도 폴리에틸렌 (LOPE) 필름에 천연항균성 물질을 코팅하는 방법을 개발하고, 이를 딸기의 포장에 적용하였다. 보다 안정한 항균제 코팅 필름의 생산을 위하여 결착제와 함께 코팅한 필름의 생산방법을 검토한 결과, polyamide수지용 과 항균생 물질을 함께 코팅함에 의하여 안정한 코팅을 행성할 수 있었다. 이의 항균성을 미생물 평판 배지 상에서 확인한 결과, 1% 자몽종자추