Number Of Total Aerobic Bacteria Research Articles

Shelf-life study of a vegetable-based juice prepared using a masticating juicer


 Background Home juicing has seen a rise in popularity because it gives people an appetizing way to get their daily intake of fresh fruits and vegetables. The roles of proper refrigeration, pasteurization, and acidification are all important in regards to determining the shelf life of a freshly made juice. As the general public may not properly understand these implications, this could become a major concern for public health officials. Methods A vegetable-based juice, made with carrots, celery, apples and parsley was made using a masticating juicer. Two versions of the juice were made, one original and one acidified. The pH, total coliforms, and total bacterial levels were monitored in both versions of the juice over a fifteen-day period. Results Analyses were carried out with the two juice samples. The pH values of the two juices were significantly different (p = 0.0000). No statistically significant difference was found in either the total number of aerobic bacteria or coliforms in the acidified and original juices. The relationship between total bacterial count and pH in the both the acidified and neutral juices were statistically significant, r= 0.7659, p= 0.0098 and r=0.7334, p=0.0158, respectively. No statistically significant correlation was found between coliforms and pH. Conclusion Although it was expected that the acidified juice would have had a lower levels of bacterial growth, this research project failed to show this. The total bacterial levels in the acidified juice was greater than 106 CFU/g on Day 8 and the original juice was greater than 106 CFU/g on Day 10. Regardless of the pH, the safest and lowest bacterial levels will be right when the juice is made.

Assessment of the Microbiological Quality of Vegetable from Urban Community Gardens in Korea

Many community gardens in large cities worldwide grow vegetables; however, no information regarding the levels of sanitary indicator bacteria and prevalence of foodborne pathogens in vegetables grown in urban community gardens is available. To evaluate the microbiological quality of vegetables from urban community gardens in Korea, 530 samples (nine types of vegetable, including Chinese cabbage, lettuce, radish leaves, spinach, mustard leaves, crown daisy, leek, Korean cabbage, and chicory) were collected at 11 urban community gardens in Seoul, Korea from September through October 2012. The levels of total aerobic bacteria, Escherichia coli, total coliforms, Salmonella spp. Listeria monocytogenes, and E. coli O157:H7 were evaluated quantitatively and/or qualitatively. The mean numbers of total aerobic bacteria and coliforms were 6.3 log CFU/g (range 3.8-8.1 log CFU/g) and 4.3 log CFU/g (range 2.1-6.4 log CFU/g), respectively. Total coliforms were detected on 67% of whole vegetables. Chicory showed the highest number of total aerobic bacteria and coliforms, whereas the lowest number of coliforms was detected on leeks. E. coli was detected on 2.3% of whole vegetables, including lettuce, radish leaves, mustard leaves, and chicory; however, foodborne pathogenic bacteria were not detected on any of the vegetable samples using this highly sensitive and validated procedure. Based on these findings, the presence of coliforms and E. coli demonstrates that opportunity for improvement of microbiological safety exists throughout the produce production chain, although no major foodborne pathogens were present in vegetables grown in urban community gardens.

차아염소산나트륨 세척 및 진공 포장이 노계 가슴육의 냉장 저장 중 미생물학적 및 이화학적 품질에 미치는 영향

Department of Agricultural Biotechnology, Seoul National University, 151-921, KoreaABSTRACT This study was conducted to examine the effect of spray-washing old hens (old laying hens, old molting hens and old breeder hens) carcasses with sodium hypochlorite (50 ppm) solution and vacuum packaging on the microbiological and physiochemical quality of breast meat during storage at 4. There were no significant differences of cooking loss and texture among breast meats from different birds with spray-washing by water or sodium hypochlorite solution before storage. The numbers of total aerobic bacteria of aerobically packaged and only water-washed breast meat were higher than 7 Log CFU/g (the limitation population for spoilage of meat) after 7 days of storage. However, the numbers of total aerobic bacteria of vacuum packaged breast meat washed by sodium hypochlorite solution were lower than 7 Log CFU/g even after 14 days of storage. The volatile basic nitrogen content of vacuum packaged breast meat were lower than 20 mg% (the limitation value for spoilage of meat) regardless of the washing method, while those of aerobically packaged breast meat washed by tap water and sodium hypochlorite solution were 41.1 and 20.1 mg%, respectively. In addition, lipid oxidation and change of pH in breast meat was inhibited by vacuum packaging when compared with that of aerobic packaged breast meat during storage. Therefore, the results indicated that the washing old hen’s carcasses with sodium hypochlorite (50 ppm) solution and vacuum packaging could improve the shelf-life of meat from old birds. This result can provide the basic information for industry, which are seeking for export market.(Key words : old hen, sodium hypochlorite, vacuum packaging, shelf-life)Authors, Jae Cheon Na and Sun Hyo Kim contributed equally as co-first authorship.

Impact of Sampling Area and Location on Measurement of Indicator Organisms during Beef Carcass Interventions

The effect of the sponge sample collection site on the recovery of multiple indicator organisms from beef carcass surfaces was evaluated to simplify and validate our previous sampling method for ease of implementation as a general protocol. Sponge samples were collected at three beef processing plants using hot water or acidic antimicrobials as interventions. Two 4,000-cm(2) samples were collected from preevisceration carcasses (n = 248), one from the inside and outside round area (top site) and one from the navel-plate-brisket-foreshank area (bottom site). One-half of the samples (n = 124) were collected before a wash cabinet intervention and the other half after the intervention. The numbers of total aerobic bacteria, Enterobacteriaceae, coliforms, and Escherichia coli were determined for one-half of each individual sponge sample. The other halves of the sponges were combined to represent a top plus bottom 8,000-cm(2) SAMPLE: For the preintervention carcasses, 4,000-cm(2) samples collected from the top or bottom sites of the carcasses were not significantly different (P > 0.05) from each other or from the 8,000-cm(2) combined sample in recovery of the indicator organisms. Significant reductions of indicator organisms were observed in all three types of sponge samples after intervention; however, samples collected from the bottom site recovered less organisms (P < 0.05) compared with samples of the other types. These results suggested that samples collected from either the top or the bottom site of the carcasses with this method are suitable for monitoring indicator organisms as long as the same sampling site is consistently used.

Detection of microbial contaminants of some locally produced fruit juices, ice creams, and yogurts.

The study included (45) samples of fruit juices, ice creams and yogurts which locally produced and available at Baghdad markets including some small markets and booths. The study focused on the detection of microbial contaminants by accounting total number of aerobic bacteria, coliform bacteria, E.coli, S. aureus and Salmonella. Results of microbial tests of (20) randomly collected samples of juices selected from local stores and boxes in Baghdad city area showed contamination and invalidity of these samples for human consumption comparing to Iraqi standards with a failure rate reached to 15% for total count of bacteria, 10% for coliform. The microbial test (15) samples showed a failure rate of 66.5% for aerobic bacteria (T.C) , 60% for E.coli, 65.6 % for coliform bacteria , 13.3 % for staphylococcus aureus.No sign if Salmonella existence was recorded for all tested samples in compare with Iraqi standards. As for yogurts, the microbial tests of (10) samples showed a failure rate of 30% for coliform, no sign of Salmonella existence was recorded for all tested samples.

적양배추싹의 Shelf Life 예측 및 Aqueous ClO2, Fumaric Acid, UV-C 병합처리

To estimate the shelf life of red cabbage sprouts (stored at 4 and ), the numbers of total aerobic bacteria were determined during storage. Parameters for the Gompertz model were determined and the shelf life was predicted using a modified Gompertz equation. The estimated shelf lives of red cabbage sprouts packed with polyolefin film and polyamide/polyamide/polyethylene (PA/PA/PE) film at were 49.4 and 52.3 h, respectively, whereas those of red cabbage sprouts packed with polyolefin film and PA/PA/PE film at were 19.7 and 22.6, respectively. The shelf life prediction equation was appropriate, based on the statistical analysis of the accuracy factor, bias factor, and mean square error. On the other hand, for red cabbage sprouts treated with aqueous /fumaric acid and UV-C then packed with polyolefin film or PA/PA/PE film, the shelf life was predicted to be longer than 168 h. These results suggest that the combined treatment of aqueous /fumaric acid and UV-C can be useful for improving microbial safety and extending the shelf life of red cabbage sprouts during storage.

보육시설 유아 사용 수건의 미생물 분포 및 독소 특성

어린이집 유아들이 공용으로 사용하는 수건의 미생물 오염도와 분리된 식중독 미생물의 장독소 유전자 및 장독소 생산 특성을 분석하여 어린이집 유아 사용 수건의 위생안전성을 확보하고자 어린이가 손 씻은 후 공용으로 사용하는 수건 22개 (사용 전 7개, 사용 중 15개)를 연구대상으로 하였다. 일반세균수는 평균 6.2 log CFU/100 <TEX>$cm^2$</TEX>로 검출되었고 진균수는 평균 4.1 log CFU/100 <TEX>$cm^2$</TEX>로 검출되었으며 대장균군은 사용 전 수건의 경우 7건 중 4건 (57.1%), 사용 중인 수건의 경우 15건 모두에서 (100%) 검출되었다. 어린이 사용 수건의 미생물 오염도가 높게 나타나 수건의 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 유전자와 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% 검출되었다. 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 상존하는 것으로 나타나 개인별 수건 또는 종이 타올 사용을 고려하여야 할 것으로 판단되었다. This study was conducted to evaluate the microbiological contamination on commonly used hand towels in the child care centers and to investigate the toxin gene and toxin production ability of food-borne pathogens. A total of 22 commonly used hand towels including 7 for before use and 15 for during use were tested. The average number of total aerobic bacteria and fungi were 6.2 log CFU/100 <TEX>$cm^2$</TEX> and 4.1 log CFU/100 <TEX>$cm^2$</TEX>. Coliform bacteria were detected in 4 out of 7 before used towels (57.1%) and all of during used towels (100%). These results showed that the sanitary conditions of hand towels in the child care centers should be improved promptly. Among the pathogenic bacteria, Staph. aureus and B. cereus without Salmonella spp. were detected in 5 (22.7%) and 11 (50.0%) out of 22 hand towels. All of Staphy. aureus isolated in this study did not possess any toxin genes and did not produce enterotoxin. The detection rate of hblC, hblD, and hblA toxin genes in B. cereus was 72.7, 72.7, and 54.5% respectively. The possession rate of nheA, nheB, and nheC toxin genes showed 81.8, 72.7, and 54.5% respectively. The cytK and entFM toxin genes were presented at 45.5 and 90.0% in B. cereus. The HBL was detected in 8 out of 11 B. cereus isolates (72.7%) and 5 B. cereus isolates produced NHE (45.5%). Ten out of eleven B. cereus isolates (90.9%) produced one or more enterotoxin such as HBL and NHE. From the results, using a private hand towel or paper towel is required to prevent the cross-contamination between commonly used hand towel and children's hands in the child care center.

액상칼슘을 첨가한 육류조리용 간장양념 및 그 제조방법

In this study, liquid calcium was used to develop a calcium-fortified soy sauce-based seasoning for meat and the quality characteristics of the seasoning and cooked meat were investigated. All seasonings with different amount of liquid calcium (0, 2, 4, or 8%) showed no significant changes in pH and titratable acidity at for 9 days; however, the control seasoning and seasoning with 2% liquid calcium (Ca-2%) showed significant decreases in pH and increases in titratable acidity during storage at for 9 days, compared to the seasoning with 4% (Ca-4%) and 8% (Ca-8%) liquid calcium. We also observed that during storage at , the numbers of total aerobic bacteria, lactic acid bacteria, and yeast were significantly lower in Ca-4% and Ca-8% seasoning compared to the control or Ca-2%. The calcium contents in cooked meat seasoned with the control, Ca-2%, Ca-4%, or Ca-8% were 2.16, 33.47, 54.72, and 58.23 mg/100 g, respectively. Sensory evaluations demonstrated no significant differences in flavor, taste, juiciness, texture, and overall acceptability between the cooked meat samples. These results suggest that soy sauce seasoning supplemented with liquid calcium (2~8%) effectively increases the calcium content in cooked meat without adversely affecting its taste, flavor, and juiciness. Thus, this type of calcium-fortified seasoning may be helpful in combating the lack of calcium in modern diets.

가공 및 저장 방법이 다른 오리 가슴육의 기계적 판별

본 연구는 오리 신선육과 냉동 후 해동육의 구별을 손쉽게 할 수 있는 방법을 제시하고, 오리육의 처리형태별 저장기간에 따른 미생물, 드립감량, 관능검사 등 품질변화를 연구하여 기계적 방법(토리미터)을 이용한 신선도 측정 시 객관적인 등급판정 기준을 제시하기 위해 실시되었다. 오리가슴육 중 냉동 후 해동육 껍질(skin)색에서 신선육이나 토치육에 비해 명도가 낮아지고, 적색도가 증가하였으며, 드립감량은 냉동 후 해동육이 다른 처리구에 비해 유의적으로 높았다(p<0.05). 일반 호기성 미생물은 1일차에서 토치육이 신선육에 비해 낮았으나 3 및 7일차에는 모든 처리구간에 유의적인 차이는 없었다. TBARS값은 저장기간 동안 증가하였으나 처리구간 유의적인 차이를 보이지는 않았다. 관능검사결과 냉동 후 해동육이 관능검사의 모든 항목에서 유의적으로 낮은 결과를 나타내었다(p<0.05). 토리미터 값은 오리 가슴 껍질(skin)과 육(meat) 모두에서 냉동 후 해동육이 다른 처리구에 비해 유의적으로 낮게 나타났다(p<0.05). 오리육의 토리미터값과 품질특성과의 상관관계를 분석한 결과 육색을 제외한 일반호기성미생물, 지질산패도, 드립감량 및 저장기간과의 밀접한 관계가 있는 것으로 확인되었다. 이상의 결과에서 냉동 후 해동된 오리 가슴육은 신선육이나 토치육에 비해 육색의 변화나 드립 감량 증가가 빠르게 이루어짐을 알 수 있었고, 토리미터 값의 측정은 냉동 후 해동육을 신선육이나 토치육으로부터 구별하는 신속한 방법으로 이용이 가능할 것으로 사료된다. The possibility of instrumental differentiation of duck breast meat treated with different processing and storage conditions was investigated for industrial application. Duck breast meats, which were 1) refrigerated (fresh) after slaughter, 2) fresh but applied the torching process for the removal of remaining feathers (fresh-torched), and 3) frozen and thawed (frozen-thawed), were prepared and the torrymeter value and other quality factors were assessed. The torrymeter values of both duck breast meat and skin showed the lowest in frozen-thawed sample during the whole storage period. The drip loss of frozen-thawed sample was higher than those of fresh or fresh-torched ones. The number of total aerobic bacteria was lower in fresh-torched than fresh but both were not different from frozen-thawed at day 1 while no difference found thereafter. Sensory score of frozen-thawed sample was the lowest. The correlation analysis among the torrymeter value and quality factors of duck breast meat revealed that the torrymeter value is closely related with the total aerobic bacterial number, lipid oxidation, drip loss, and storage period but not with color. The results indicate that once the duck breast meat was frozen then thawed, drip loss and sensory quality can be affected and the torrymeter value can differentiate frozen-thawed from fresh and freshtorched duck breast meat.

Changes in the aerobic vaginal bacteria load and antimicrobial susceptibility after different oestrous synchronisation treatments in goats

The objectives of this study were to determine (i) the variation in the bacterial population, (ii) the changes in the number of aerobic bacteria, and (iii) in vitro bacterial susceptibility to different antibiotics after the use of two different intravaginal devices (silicone devices or polyurethane sponges) for 6 or 11 days in goats. During the breeding season, 25 multiparous Saanen goats were randomly allocated to four treatments. Group IS-6 (n = 6) and Group IS-11 (n = 6) goats received a polyurethane intravaginal sponge (60 mg medroxyprogesterone acetate with oxytetracycline in powder) during 6 or 11 days, respectively. Goats from groups SD-6 (n = 7) and SD-11 (n = 6) received an intravaginal silicone device (0.3 g progesterone) during 6 or 11 days, respectively. Before the introduction of the devices, at device withdrawal, and the day of oestrus we performed standard bacteriological procedures on vaginal mucus samples. The predominant bacterial flora at device insertion was gram-positive (77%), and the most frequent strain was Bacilllus sp. The samples obtained on Day 6 [SD-6: 9/12 (75.0%); IS-6: 5/9 (55.5%)] and Day 11 [SD-11: 3/4 (75.0%); IS-11: 5/5 (100%)] were predominantly gram-negative, and the most frequently isolated bacteria was Arcanobacterium pyogenes. The total number of aerobic bacteria forming colony units (CFU/mL) was greater in goats treated with inert silicon device that those treated with intravaginal sponges (P = 0.028). On device removal (Days 6 and 11), we observed more CFU/mL than on device insertion. We observed no difference in CFU/mL on day of oestrus with respect to the day of device insertion (Day 0: 41.1 ± 19.3; Day 6: 187.1 ± 51.3; Day 11: 169.1 ± 27.8; day of oestrus: 20.1 ± 25.8 CFU × 103/mL; P &lt; 0.05). The in vitro studies demonstrated that most samples were resistant to oxytetracycline. We concluded that the use of intravaginal devices, regardless of their composition, provoked an increase in the normal vaginal bacterial flora, but values returned to pre-insertion numbers by the day of oestrus. According to in vitro results, amoxicillin, ampicillin and streptomycin were the most effective antibiotics to prevent vaginal bacterial growth.

곤드레 첨가량을 달리한 곤드레 두부의 저장기간에 따른 품질특성

This study examined the quality characteristics of Gondre tofu containing 0, 0.1, 0.2, and 0.3% Cirsium setidens powder. Quality and sensory tests of Gondre tofu were performed. The yield rate of tofu decreased with the addition of Cirsium setidens powder. The pH of tofu decreased after the addition of Cirsium setidens powder. During 8 days storage, the addition of Cirsium setidens powder to tofu did not effectively inhibit the number of total aerobic bacteria. The L, a and b values of tofu decreased with increasing amount of Cirsium setidens powder added. In the texture properties, the hardness, cohesiveness, gumminess and brittleness increased, whereas the springiness decreased. The results of sensory evaluation showed that tofu containing 0, 0.1, and 0.2% Cirsium setidens powder had a higher taste, texture preference and overall acceptability than 0.3% Cirsium setidens powder. Therefore, the addition up to 0.2% Cirsium setidens powder positively affects the sensory evaluation of Gondre tofu. The addition 0.2% Cirsium setidens powder might be considered the most appropriate choice for manufacturing Gondre tofu.

Bactericidal effects of lettuce after subsequent washing with hypobromous acid and sodium hypochlorite

Sodium hypochlorite (NaClO) is widely used as a sanitizer to maintain microbial safety of lettuce; however, NaClO treatment is insufficient on pathogen reduction due to its high instability for an extended storage time. Hypobromous acid (HOBr) as another sanitizer, relatively stable in processing conditions, was applied to lettuce. The numbers of total aerobic bacteria, Escherichia coli, Salmonella Typhimurium, and Staphylococcus aureus were evaluated on lettuce treated with NaClO and HOBr. The population of 4 selected bacteria on lettuce reduced more than 2.5 log CFU/g. Bactericidal effect maintained for 10 days in combined treatment with 100 mg/L NaClO followed by 200 mg/L HOBr, while the population of the bacteria without HOBr treatment increased. Combined treatment on lettuce can give synergistic effect on reducing microbial population. Residual bromine was not detected on the lettuce treated with HOBr after washed with water for 30 s, indicating that bromine was effectively washed away.

Effect of Atmospheric Pressure Plasma Jet on Inactivation of Listeria monocytogenes, Quality, and Genotoxicity of Cooked Egg White and Yolk

The objective of this study was to evaluate the effects of an atmospheric pressure plasma (APP) jet on L. monocytogenes inactivation, quality characteristics, and genotoxicological safety of cooked egg white and yolk. APP treatment using He gas resulted in a 5 decimal reduction in the number of L. monocytogenes in cooked egg white, whereas that using <TEX>$He+O_2$</TEX>, <TEX>$N_2$</TEX>, and <TEX>$N_2+O_2$</TEX> decreased the number further, and to undetectable levels. All treatments of cooked egg yolk resulted in undetectable levels of inoculated L. monocytogenes. There were no viable cells of total aerobic bacteria after APP treatment on day 0 while the control showed approximately 3-4 Log CFU/g. On day 7, the numbers of total aerobic bacteria had increased by approximately 3 log cycles in cooked egg white, but there were no viable cells in cooked egg yolk after 2 min of APP jet. APP treatment decreased the <TEX>$L^*$</TEX>-values of cooked egg white and yolk significantly on day 0. No significant sensory differences were found among the cooked egg white samples, whereas significant reductions in flavor, taste, and overall acceptability were found in cooked egg yolks treated with APP jets. SOS chromotest did not reveal the presence of genotoxic products following APP treatments of cooked egg white and yolk. Therefore, it can be concluded that APP jets can be used as a non-thermal means to enhance the safety and extend the shelf-life of cooked egg white and yolk.

어린이집 급식실 정수기의 미생물학적 오염 평가

In this study, the prevalence of microbiological hazard on water purifiers at lunchroom in child care center was investigated. A total of 49 water purifiers and their purified cold water were sampled to test about the total aerobic bacteria, coliform bacteria, Bacillus cereus, Staphylococcus aureus, and Salmonella spp. Total aerobic bacteria was detected over 2.0 log CFU/mL in 6 out of 49 purified cold water (12.2%), ranged from 2.0 to 2.4 log CFU/mL, and the average number of total aerobic bacteria was showed to be 3.3 log CFU/drain spout. The drain spout turned out to be a major contaminant in water purifier and needs to be improved. Coliform bacteria were also detected in 7 out of 49 cold faucets (14.3%) and 7 out of 49 drain spouts (14.3%), but not detected in purified cold water. All samples were not contaminated with the pathogens tested in this study, except for B. cereus, which was contaminated on 2 out of 49 cold faucets (4.1%) and 4 out of 49 drain spouts (8.2%). All of B. cereus isolates produced enterotoxin, such as heamolysin BL enterotoxin (HBL) or non-heamolytic enterotoxin (NHE). The HBL was detected in 5 out of 6 B. cereus isolates (83.3%), including B. cereus PCF-11 and B. cereus PDS-30 isolate only produced NHE (16.7%). These results showed that the sanitary conditions of cold faucets and drain spouts should be improved promptly.

Microbial kinetics, fermentative and chemical characteristics in solid state fermentation of apple bagasse

The objective of this study was to evaluate the microbial kinetics, fermentative and chemical characteristics during solid state fermentation (SSF) of apple bagasse (AB), which was determined over the course of 4 incubation times: 0, 24, 48, 72 h, in a completely randomized design with 4 repetitions. pH values, lactic acid concentration, numbers of total aerobic bacteria, yeast and lactobacilli, dry matter digestibility and neutral detergent fiber digestibility were determined. True and crude protein, neutral and acid detergent fiber were also measured. Results revealed that pH decreased over the 4 sampling times. The lactic acid concentration increased over time. There was a reduction in numbers of total aerobic bacteria. Numbers of lactobacilli also reduced. Yeast populations (CFU/ml) were stable at 24 h, but decreased thereafter. In vitro dry matter digestibility (IVDMD) increased during incubation. In vitro neutral detergent fiber digestibility (IVNDFD) similarly increased, with a maximum value observed at 72 h. True protein (TP) increased during fermentation, achieving a high value at 24 h; however, crude protein (CP) showed no change during incubation. Neutral detergent fiber (NDF) content did not change during fermentation however acid detergent fiber (ADF) reduced. It is concluded that the increased content of lactic acid and the accompanying decrease in pH during SSF of AB negatively affected the yeast and total bacteria populations whereas true protein content increased likely because of formation of unicellular protein during the process.

마늘의 유통 형태에 따른 저장 중 품질 특성

시중에 유통되고 있는 전처리 가공된 마늘의 저장 중 품질특성 변화를 알아보고자 깐 마늘과 다진 마늘을 구입하여 냉장(2℃), 냉동(-18℃) 온도에서 30일간 저장하면서 품질특성을 조사하였다. 또한 다진 마늘은 상온(20℃)에서 3일간 품질 특성 조사를 실시하였다. 깐 마늘과 다진 마늘의 색도는 저장기간이 경과할수록 L값은 감소하고 a, b값은 증가하여 갈변화가 진전됨을 나타내었다. 깐 마늘의 중량감모율은 저장기간에 따라 유의하게 증가하였으며, 냉동저장구의 증가율이 냉장저장구에 비해 높았다. 부패율과 맹아율은 냉동저장구에서는 거의 발생하지 않았으며 냉장저장구는 유의하게 증가하였다. 깐 마늘의 경도는 냉동에 의해 급속히 감소하였으나, 냉장 및 냉동온도에서 저장기간에 따른 차이는 없었다. 냉동저장 한 깐 마늘과 다진 마늘의 드립로스 또한 저장기간 경과에 따른 유의한 변화를 보이지 않았다. 냉장저장 한 깐 마늘과 다진 마늘의 총 세균수는 저장기간에 따른 유의한 변화를 보이지 않았으며, 냉동저장의 경우에는 감소하는 경향을 보였다. 반면 상온저장 한 다진 마늘의 총 세균수는 서서히 증가하는 경향을 보였다. 마늘의 풍미 성분 지표인 pyruvic acid는 다진 마늘의 저장 전 함량이 깐 마늘보다 높았다. 저장기간 동안 깐 마늘의 pyruvic acid는 증가하였으며 다진 마늘은 감소하는 것으로 나타났으며, 냉장저장이 냉동저장보다 변화폭이 더욱 크게 나타났다. 위의 실험결과 전처리 가공 형태 및 저장온도가 저장기간 동안 마늘의 품질 특성 변화에 영향을 미치는 것을 알 수 있었고, 마늘의 품질유지를 위해 적절한 저장온도 설정 및 관리가 필요한 것으로 사료되었다.

Effect of Storage on Microbiological Quality of Honey

Abstract One hundred and nine samples of honey representing different botanical types were microbiologically retested for the total number of aerobic bacteria per 1 g, the presence of anaerobic bacteria in 0.1 g, and number of yeasts and moulds per 1 g after one year of storage. The samples displayed different levels of microbiological contamination. The mean of total number of aerobic bacteria varied from 1.9 x 101 CFU/g to 4.6 x 103 CFU/g depending on the type of honey. This value, in comparison with year 2010 was lower in the case of 75 samples (68.8%), higher in 14 samples (12.8%), and stable in the remaining 20 samples (18.4%). The mean number of moulds and yeasts was 9.8 x 101 CFU/g and it was lower in 46 samples (42.2%). In 46 samples no changes were noted. The presence of anaerobic spore forming bacteria was noted in 18 samples. The presence of these microorganisms in 73 honey samples (67.0%) did not change since 2010.

닭 다리 분쇄육에 초고압 처리시 Phosvitin의 첨가가 미생물학적 품질과 지방 및 단백질 산화에 미치는 효과

본 연구는 초고압 처리가 부분육으로 유통되는 닭 다리 분쇄육의 저장 안전성에 미치는 효과와 난황 phosvitin 첨가가 지방 및 단백질의 산화 안정성에 미치는 효과를 확인하기 위하여 수행되었다. 분쇄된 닭 다리육에 phosvitin을 각각 500 및 1000 mg/kg 첨가 후 비가열 또는 가열하고, 초고압 처리(300 및 600 MPa, 5분, <TEX>$15{\pm}3^{\circ}C$</TEX>)에 따른 총 호기성 미생물, 지방 및 단백질산화 및 육색의 변화를 <TEX>$4^{\circ}C$</TEX>에서 7일간 저장 하면서 측정하였다. 연구 결과 생육에서 300 및 600 MPa 처리에 의해 총 호기성 미생물의 증식이 저장 7일 후 각각 4 및 5 Log CFU/g 정도 억제 되었으며(p<0.05), 600 MPa 처리에 의해 지방 및 단백질산화가 촉진됨이 확인되었다(p<0.05). 초고압 처리압력 증가에 따른 <TEX>$L^*$</TEX> 값의 증가와 <TEX>$a^*$</TEX> 및 <TEX>$b^*$</TEX> 값의 감소가 확인되었다(p<0.05). 가열육은 초고압 처리와 무관하게 총 호기성 미생물의 증식이 일어나지 않았으며, 저장 7일 후 600 MPa 처리에 의한 지방의 산화가 확인되었고, 단백질의 산화는 저장 3일차에서만 600 MPa처리에 의해 유의적으로 증가함이 나타났다(p<0.05). 이상의 결과를 종합해 볼 때 초고압 처리는 부분육으로 유통되는 닭 다리 분쇄육의 저장 안전성을 높일 수 있으며, 초고압 처리시 발생하는 지방 및 단백질의 산화와 육색의 변화를 억제하기 위한 항산화제로서 phosvitin의 이용은 제한적일 것으로 생각된다. The objective of this study was to investigate the effect of high pressure (HP) processing on shelf life, as well as the addition of phosvitin on lipid and protein oxidation stability of minced chicken leg meat. Minced chicken leg meat was mixed with yolk phosvitin at 500 or 1000 mg/kg meat levels, and divided into raw and cooked groups. Then, the samples were subjected to HP at 0.1, 300, and 600 MPa. The total aerobic bacteria, lipid and protein oxidation, along with instrumental meat color (<TEX>$L^*$</TEX>, <TEX>$a^*$</TEX>, and <TEX>$b^*$</TEX>value) of the samples were measured during storage for 7 d at <TEX>$4^{\circ}C$</TEX>. In raw meat, the number of total aerobic bacteria was decreased by HP at 300 MPa (4 Log reductions) and 600 MPa (5 Log reductions) after 7 d of storage (p<0.05). HP at 600 MPa increased lipid oxidation of samples at all storage days and protein oxidation of samples during storage at 3 and 7 d. HP induced the changes of meat color by increase of <TEX>$L^*$</TEX> value and decrease of <TEX>$a^*$</TEX> value (p<0.05). The total aerobic bacteria was not detected in the cooked samples, regardless of HP pressure, and the lipid or protein oxidation of the cooked sample treated by 600 MPa was higher than that of the control (0.1 MPa) on day 7 or control on day 3, respectively (p<0.05). The results suggested that HP can improve the shelf life of minced chicken leg meat. However, phosvitin might be a limited antioxidative agent for the improvement of oxidation stability induced by HP.

어린이집 유아 손의 미생물학적 위해 평가 및 손 씻기 교육의 효과

어린이집 유아 손의 미생물 오염도를 분석하고 손 씻기 교육의 미생물 저감화 효과를 실험하여 어린이집 유아 손의 위생 안전성을 확보하고자 어린이집 유아 59명을 대상으로 실험하였다. 일반세균수의 경우 평균 <TEX>$3.72{\pm}0.38log\;CFU/hand$</TEX>로 검출되었고, 위생지표미생물인 대장균군의 경우 남자어린이 18명 중 2명(11.1%)과 여자어린이 17명 중 3명(17.6%), 총 35명 중 5명(14.3%)에서 검출되어 어린이들에 대한 반복적인 손 씻기 지도가 필요한 것으로 판단되었다. <TEX>$Staph.$</TEX> <TEX>$aureus$</TEX>는 35명 중 9명(25.7%), <TEX>$B.$</TEX> <TEX>$cereus$</TEX>는 35명 중 16명(45.7%)에서 검출되었고 남자어린이의 손이 식중독 미생물 오염에 가장 취약한 것으로 나타났다. <TEX>$Staph.$</TEX> <TEX>$aureus$</TEX> 장독소는 9균주 중 <TEX>$Staph.$</TEX> <TEX>$aureus$</TEX> Hand-1 한 균주에서만 SEA 장독소가 검출되었으나 HBL과 NHE 장독소 중 한 가지 이상의 장독소를 생산하는 <TEX>$B.$</TEX> <TEX>$cereus$</TEX>는 총 12균주(70.0%)로 나타나 어린이 손에 의한 교차오염 위험성이 상존한다고 판단되었다. 손 씻기 교육의 미생물 저감화 효과를 실험한 결과 교육을 실시한 그룹이 0.18 log CFU/hand 일반세균수가 더 저감화가 되었으나 저감화 정도가 매우 미약하여 손에 부착되어 있는 세균을 완전히 제거하기 위해서는 손 씻기와 손 소독을 병행하며 지속적인 손 씻기 교육을 실시하여야할 것으로 판단되었다. This study was conducted to evaluate the microbiological hazard on nursery school children's hands and to investigate the reduction effect of hand washing education. A total of 59 nursery school children's hands were tested. The average number of total aerobic bacteria was <TEX>$3.72{\pm}0.38log\;CFU/hand$</TEX>. Five children's hands(2 male and 3 female) were positive(14.3%) for the coliform bacteria. These results showed that hand washing education are required repetitively. Among the pathogenic bacteria tested in this study, <TEX>$Staphylococcus$</TEX> aureus and <TEX>$Bacillus$</TEX> <TEX>$cereus$</TEX> were detected in 9(25.7%) and 16(45.7%) out of 35 their hands, respectively. Twelve out of sixteen <TEX>$B.$</TEX> <TEX>$cereus$</TEX> isolates(70.0%) produced enterotoxin. The results indicate that the hand hygiene of nursery school children needs to be improved. Comparing before and after hand washing in educated and non-educated group, the reduction effect of total aerobic bacteria on their hands was 0.42 and 0.60 log CFU/hand, respectively. The educated group showed 0.18 log CFU/hand higher reduction effect than non-educated group but microorganism did not eliminate perfectly. From the results, using a hand sanitizer after washing with soap and the continuous hand washing education are required to control the contaminated bacteria on nursery school children's hands.

Comparison of the efficacy of gamma and UV irradiation in sanitization of fresh carrot juice

As there is no pasteurization procedure for the manufacture of fresh vegetable juice, both industry and consumers have sought a method for improving the storage stability and shelf-life of this category of products. In this study, the effects of commercially available, non-thermal pasteurization processes, such as gamma and UV irradiation, were compared for their efficacy in sanitizing fresh carrot juice (FCJ). FCJ was manufactured, packaged, and gamma irradiated with doses of 0, 1, 3, and 5kGy. The manufactured FCJ was also passed through 4 UV light lamps at doses of 3.67, 4.69, and 6.50kGy. The total aerobic bacterial count of the FCJ approached the legal limit (105 CFU/mL) after manufacturing. Both treatments were effective in reducing the number of total aerobic bacteria, and the reduced number was maintained during storage for 7 days. Gamma irradiation was more effective in suppressing microbial growth during storage. When the doses for UV treatment and gamma irradiation were higher, the inactivation effects were higher. The reduction of ascorbic acid content was greater upon gamma irradiation than UV treatment. No difference was found in the contents of flavonoids and polyphenols in FCJ after either treatment. After 3 days of refrigerated storage, the sensory scores of gamma- or UV-irradiated FCJ were superior to those of the control. The results indicate that both non-thermal treatments were effective in improving storage stability and extending shelf-life, but gamma irradiation was slightly better in suppressing microbial growth after treatment.