微酸性电解水对鲜米线杀菌及保鲜效果的研究

为探讨微酸性电解水(Slightly acidic electrolyzed water, SAEW)对鲜米线储藏过程中的杀菌及延长保鲜期的作用,以鲜米线为研究对象,对不同的有效氯浓度、浸泡时间、料液比进行试验,研究了最佳的杀菌条件。采用响应面分析法(RSM)对微酸性电解水的杀菌条件进行优化,从而确定微酸性电解水杀菌的最佳参数。结果表明:最佳参数为有效氯质量浓度32 mg/L、浸泡时间9 min、料液比1︰11 g/mL,鲜米线表面的减菌数量为3.24±0.03 lg(CFU/g)。在此条件下,在储藏48 h内鲜米线表面减菌数随时间延长而增加。依据鲜米线菌落总数质量标准,试验组鲜米线保鲜期比对照组延长约16 h,从而降低了鲜米线腐败变质的速率。     

微酸性电解水杀灭菠菜表面微生物的影响因素

采用微酸性电解水对菠菜进行杀菌处理,考察微酸性电解水对菠菜的杀菌效果及影响因素,包括不同杀菌剂杀菌效果比较、浸泡时间、处理方式及与强碱性电解水预处理、超声波辅助处理联用对杀菌效果的影响,同时对处理过程中微酸性电解水有效氯浓度(ACC)、pH值、氧化还原电位(ORP)的变化进行分析。结果表明:微酸性电解水(ACC 31.73mg/L、pH 5.92、ORP 836.5mV)的杀菌效果明显优于相同ACC的次氯酸钠溶液;随着ACC的升高微酸性电解水的杀菌效果逐渐增强,当ACC增至31.37mg/L时可使微生物数降低1.69(lg(CFU/g)),ACC继续升高至67.96mg/L,杀菌效果则无显著性增强;分别对菠菜进行浸泡处理1、3、5、10min,微酸性电解水的杀菌效果无显著性差异,随着浸泡时间的延长微酸性电解水的ACC及ORP呈显著下降趋势,pH值无明显变化;采用强碱性电解水预处理和超声波辅助处理,能使微酸性电解水的杀菌效果分别提高约0.5(lg(CFU/g))、1.0(lg(CFU/g));采用微酸性电解水浸泡处理杀菌效果优于冲洗处理。     

微酸性电解水杀菌工艺优化及对云南鲜米线贮藏品质影响

为优化微酸性电解水（Slightly Acidic Electrolyzed Water,SAEW）对鲜米线杀菌工艺条件,探明其对米线储藏过程品质变化规律;以微酸性电解水处理温度、处理时间与料液比为自变量,鲜米线表面微生物杀灭对数值为响应值,应用响应面法优化其最佳处理条件。以最佳处理参数处理鲜米线,以无菌水处理样品作为对照组（CK）,两组样品均置于27℃恒温箱中储藏,定期测定其表面菌落总数、含水量、酸度、pH、色差等指标,探讨SAEW处理对鲜米线贮藏品质变化影响。得出其最佳处理条件为,温度21℃、时间15 min、料液比1:16（m:V）。在此工艺条件下计算所得菌落总数死亡数量级的理论值为3.09 lg CFU/g。进行3次验证实验实际平均菌落死亡数量级为（3.01±0.09） lg CFU/g。在此条件下,SAEW处理能有效控制样品表面微生物数量,同时可延缓褐变及总酸度的增加,减少水分含量的丧失,对pH无显著影响。处理后的鲜米线在贮藏储藏48 h后,表面菌落总数为7.46 lg CFU/g,总酸度为0.392 g/100 g,分别低于对照组的8.73lg CFU/g和0.49 g/100 g。色差值为39.73,水分含量0.69,高于对照组的35.57和0.65。pH为4.64。综合表明,SAEW处理野生菌不仅能控制其表面微生物增长量,还能减缓贮藏品质的劣变速度,该结果可为研究微酸性电解水在鲜湿米线加工中的应用提供理论依据。     

微酸性电解水对罗非鱼片保鲜效果的研究

为探讨微酸性电解水在罗非鱼加工应用的前景,开展微酸性电解水对罗非鱼片的保鲜效果研究。将罗非鱼片浸泡在有效氯浓度为(31. 39±1. 48) mg/L的微酸性电解水10 min后沥干装入聚乙烯保鲜袋,置于4℃下贮藏,以感官评定、挥发性盐基氮(total volatile base nitrogen,TVB-N)值、k值、菌落总数与p H等作为评价指标,测定罗非鱼片冷藏过程中的品质变化。结果表明,在贮藏期间,对照组样品TVB-N值2～3 d超过20 mg/100 g,而实验组样品第6天刚超过20 mg/100 g,对照组样品k值2～3 d超过60%,而实验组样品5～6 d超过60%,对照组样品菌落总数2～3 d超过6 lg CFU/g,而实验组样品第6天刚超6 lg CFU/g,实验组样品p H增加始终较对照组样品慢,而实验组样品感官评分始终高于对照组样品。采用微酸性电解水处理后的罗非鱼片,对比对照组货架期延长2～3 d。为微酸性电解水在水产品保鲜技术上应用提供技术参考和依据。     

不同清洗方式下克氏原螯虾肉细菌群落及理化性质的变化

该研究探讨了克氏原螯虾的三种清洗预处理方式（清洗剂清洗,CA;超声波清洗,UL;清洗剂结合超声清洗,CA+UL;对照组,CK）对克氏原螯虾虾肉的细菌群落以及理化性质的影响。测定了清洗前后小龙虾虾肉菌落总数、假单胞菌、霉菌酵母、嗜温菌、嗜冷菌、pH、质构特性和风味物质的变化。结果表明,CA+UL处理组减菌效果最好,清洗后菌落总数减少1.12 lg CFU/g,对霉菌酵母,产硫化菌,嗜冷菌也有较好的抑制效果,分别减少了0.66、0.9、0.82 lg CFU/g。而CA组与UL组对于霉菌、嗜温菌等细菌减少的效果不太明显,且清洗后虾肉pH有所上升;而CA+UL组pH变化不大;经过清洗后的虾肉品质整体有略微下降。不同清洗方式对挥发性物质也有较大的影响,产生了N-甲基异丙基胺等不良气味风味物质。因此,结合虾肉细菌群落结果与理化性质来看,超声波与清洗剂结合清洗的效果更优。     

基于初始微生物控制的冷鲜鲟鱼肉减菌工艺优化及品质控制

目的:筛选冷鲜鲟鱼肉的最佳减菌剂并建立最佳减菌工艺。方法:采用不同质量浓度二氧化氯、次氯酸钠、酸性氧化电解水、臭氧水溶液以料液比1:5浸泡鲟鱼块5 min后,用自来水冲洗30 s,沥干2 min,测定菌落总数、感官和色差,确定最优减菌剂。利用正交试验和验证试验优化并确定冷鲜鲟鱼肉减菌剂作用最佳工艺条件,并进一步开展此条件下对鱼肉品质的影响研究。结果:结合减菌率、感官评价和色差综合分析,酸性氧化电解水为冷鲜鲟鱼肉最优减菌剂。当酸性氧化电解水有效氯浓度为70 mg/L,以1:2的料液比浸泡鲟鱼块10 min后冷鲜鲟鱼的初始菌落总数为1.731 lg cfu/g,其减菌率可达96.59%。在此条件下,冷鲜鲟鱼4℃冷藏第7天菌落总数为4.64 lg cfu/g,保持在二级鲜度水平;贮藏到第11天,才超过二级鲜度指标。结论:基于初始微生物控制的冷鲜鲟鱼最优减菌剂为酸性氧化电解水,在优化的工艺条件下对冷鲜鲟鱼肉的品质具有良好的维持效果,较对照组可将货架期延长4 d。     

茶多酚对低盐中式腊肠防腐保鲜的影响

根据Box-Benhnken实验设计原理,以中式腊肠菌落总数及感官评分为指标,在单因素试验的基础上,采用 四因素三水平响应曲面分析法优化茶多酚减菌化条件。结果表明：茶多酚对中式腊肠原料肉减菌化处理的最佳工艺 条件为茶多酚溶液质量浓度0.61 g/100 mL、溶液pH值8.35、溶液温度22.03 ℃、处理时间33.44 min,在此条件下中 式腊肠的菌落总数可降至4.3（lg （CFU/g））,感官评分为89.3 分。     

超声波清洗牛肚的工艺优化

以牛肚为主要原料,研究不同超声波功率、清洗时间和清洗温度对牛肚洁净度和菌落总数的影响,优化超声波清洗牛肚的工艺条件。结果表明:在超声波功率为350 W,超声波清洗时间为30 min,清洗温度为25℃的工艺条件下,牛肚的洁净度和菌落总数分别为0.93±0.26和(5.04±1.53)(lg(CFU/g)),达到最佳清洗效果。     

基于高通量测序分析冷冻熟制小龙虾加工过程中微生物的消长规律

为揭示冷冻熟制小龙虾加工过程中微生物的消长规律并确定加工过程关键控制点,用微生物传统培养法结合高通量测序手段分析了小龙虾在原料、吐沙、清洗、蒸煮及成品等加工环节中的微生物变化情况。结果表明：吐沙环节可使虾鳃微生物数量显著下降,减菌率达98.9%,肠道中菌落总数变化不显著。蒸煮环节可使小龙虾虾鳃和肠道中的菌落总数分别降低4.22(lg(CFU/g))和4.64(lg(CFU/g)),使虾肉中的微生物含量低于检测限,并且能够完全杀灭大肠菌群和假单胞菌。高通量测序结果显示原料虾鳃及肠道中的物种丰度和多样性与虾肉相比较低,虾鳃中主要是变形菌门（Proteobacteria）,肠道中以厚壁菌门（Firmicutes）为主。吐沙环节会降低小龙虾物种丰度及多样性,虾肠道中变形菌门相对丰度显著降低,蒸煮后虾肉和虾鳃中的黄杆菌属（Flavobacterium）较清洗环节显著下降。研究确定了加工过程微生物的关键控制点为吐沙和蒸煮环节,为提升小龙虾制品质量安全和防腐保鲜提供理论依据。     

市售豆芽携带细菌种属鉴定及酸性电解水的杀菌效果

为了探究市售豆芽携带细菌种类,寻求有效的杀菌方法,采用16S r RNA基因序列分析对分离的细菌进行种属鉴定,并考察了不同p H值的酸性电解水对豆芽的杀菌效果。结果表明,分离出的5株细菌分别为Kosakonia、Staphylococcus、Klebsiella、Enterobacter和Enterobacter属成员。p H值为3.02、4.47和5.58,有效氯质量浓度为46.00 mg/L左右的酸性电解水处理市售新鲜豆芽,可以显著降低其微生物数量。p H 4.47、有效氯质量浓度为46.09 mg/L的酸性电解水处理黄豆芽,使其细菌总数、酵母菌和霉菌菌落总数、大肠菌群菌落数分别降低了1.14、2.48、1.29(lg(CFU/g)),该指标的酸性电解水处理绿豆芽,使其细菌菌落总数、酵母菌和霉菌菌落总数、大肠菌群菌落数分别降低1.23、1.42、1.25(lg(CFU/g))。因而酸性电解水对于提高市售豆芽的食用安全性可以发挥积极的作用。     

应用PCR-DGGE监测酸性电解水对虾的杀菌效果

目的：考察酸性电解水对虾的杀菌效果。样品虾处理方法为：室温(20℃)条件下酸性电解水处理不同时间(处理1min或5min);不同温度(20℃或50℃)酸性电解水处理5min;室温(20℃)条件下不同处理液(酸性电解水或2%乙酸)处理5min。利用平板培养结合PCR-DGGE技术监测酸性电解水对虾的杀菌效果。结果：50℃酸性电解水处理,虾中菌数减少1.44 lg(CFU/g),其他处理减少小于1.0 lg(CFU/g);不同处理时间对杀菌效果影响不显著;2%乙酸或50℃酸性电解水的杀菌效果显著高于室温酸性电解水(P＜0.05);PCR-DGGE指纹图谱分析结果显示：50℃酸性电解水处理后,虾中细菌种类不变,其他处理比对照(无处理)有不同程度的减少;处理1min的DGGE指纹图谱和对照极相似;50℃酸性电解水处理和对照中等不相似;其他处理和对照中等相似。结论：50℃酸性电解水对虾具有较好的杀菌效果,PCR-DGGE技术能用于监测酸性电解水对虾的杀菌效果。     

Decontamination of lettuce using acidic electrolyzed water

The disinfectant effect of acidic electrolyzed water (AcEW), ozonated water, and sodium hypochlorite (NaOCl) solution on lettuce was examined. AcEW (pH 2.6; oxidation reduction potential, 1140 mV; 30 ppm of available chlorine) and NaOCl solution (150 ppm of available chlorine) reduced viable aerobes in lettuce by 2 log CFU/g within 10 min. For lettuce washed in alkaline electrolyzed water (AIEW) for 1 min and then disinfected in AcEW for 1 min, viable aerobes were reduced by 2 log CFU/g. On the other hand, ozonated water containing 5 ppm of ozone reduced viable aerobes in lettuce 1.5 log CFU/g within 10 min. It was discovered that AcEW showed a higher disinfectant effect than did ozonated water significantly at P < 0.05. It was confirmed by swabbing test that AcEW, ozonated water, and NaOCI solution removed aerobic bacteria, coliform bacteria, molds, and yeasts on the surface of lettuce. Therefore, residual microorganisms after the decontamination of lettuce were either in the inside of the cellular tissue, such as the stomata, or making biofilm on the surface of lettuce. Biofilms were observed by a scanning electron microscope on the surface of the lettuce treated with AcEW. Moreover, it was shown that the spores of bacteria on the surface were not removed by any treatment in this study. However, it was also observed that the surface structure of lettuce was not damaged by any treatment in this study. Thus, the use of AcEW for decontamination of fresh lettuce was suggested to be an effective means of controlling microorganisms.     

浸泡时间对弱酸性电位水(SAEW)除菌效率的影响

为进一步推广弱酸性电位水(SAEW)在生鲜果蔬表面除菌上的应用,以樱桃番茄和草莓为原料,探究了不同浸泡时间(0、1、3、5、10 min)下SAEW的除菌效果。结果发现,樱桃番茄最适浸泡时间为3min,此时其表面菌落总数、霉菌和酵母、鼠伤寒沙门氏菌分别减少了1.38、1.29、1.27 lg CFU/g;浸泡时间5min后,草莓表面微生物降低值基本不再提高,菌落总数、霉菌和酵母、鼠伤寒沙门氏菌分别降低1.03、0.91、1.24 lg CFU/g。同时,研究还发现,SAEW处理后样品的呼吸速率会加快,但硬度、可滴定酸、可溶性固形物、维生素C、花青素等各项品质参数基本无变化,SAEW浸泡不会导致样品品质下降。     

酸性电解水对果蔬杀菌及保鲜效果的研究

本研究采用酸性电解水对新鲜菠菜、桃子及樱桃进行处理,考察了酸性电解水对上述果蔬在不同贮藏条件下保鲜效果的影响.结果表明,pH 3.04、有效氯浓度(ACC)30.2 mg/kg的强酸性电解水和pH 5.68、ACC 26.6 mg/kg的微酸性电解水浸泡处理5min均能使菠菜表面的微生物数下降2.0lg cfu/g以上...     

Efficacy of acidic electrolyzed water for microbial decontamination of cucumbers and strawberries

An examination was made of the efficacy of acidic electrolyzed water (AcEW, 30 ppm free available chlorine), ozonated water (5 ppm ozone), and a sodium hypochlorite solution (NaOCl, 150 ppm free available chlorine) for use as potential sanitizers of cucumbers and strawberries. AcEW and NaOCl reduced the aerobic mesophiles naturally present on cucumbers within 10 min by 1.4 and 1.2 log CFU per cucumber, respectively. The reduction by ozonated water (0.7 log CFU per cucumber) was significantly less than that of AcEW or NaOCl (P < or = 0.05). Cucumbers washed in alkaline electrolyzed water for 5 min and then treated with AcEW for 5 min showed a reduction in aerobic mesophiles that was at least 2 log CFU per cucumber greater than that of other treatments (P < or = 0.05). This treatment was also effective in reducing levels of coliform bacteria and fungi associated with cucumbers. All treatments offered greater microbial reduction on the cucumber surface than in the cucumber homogenate. Aerobic mesophiles associated with strawberries were reduced by less than 1 log CFU per strawberry after each treatment. Coliform bacteria and fungi associated with strawberries were reduced by 1.0 to 1.5 log CFU per strawberry after each treatment. Microbial reduction was approximately 0.5 log CFU per strawberry greater on the strawberry surface than in the strawberry homogenate. However, neither treatment was able to completely inactivate or remove the microorganisms from the surface of the cucumber or strawberry.     

Effects of slightly acidic low concentration electrolyzed water on microbiological, physicochemical, and sensory quality of fresh chicken breast meat

Anticmicrobial effect of slightly acidic low concentration electrolyzed water (SlALcEW) and strong acidic electrolyzed water (StAEW) on fresh chicken breast meat was evaluated in this study. Meat samples each of 10 ± 0.2 g in weight and 2.5 × 2.5 cm2 in size were experimentally inoculated with Listeria monocytogenes (ATCC 19115) and Salmonella Typhimurium (ATCC 14028) and subjected to dipping treatment (22 ± 2 °C for 10 min) with SlALcEW and StAEW. Shelf-life study was conducted for inoculated and noninoculated meat samples treated with SlALcEW and StAEW at storage temperatures of 5, 15, and 25 °C. Dipping treatment with electrolyzed water significantly (P < 0.05) reduced the background and inoculated pathogens compared to untreated controls. The reduction of 1.5 to 2.3 log CFU/g was achieved by SlALcEW and StAEW against background flora, L. monocytogenes and Salmonella Typhimurium. There was no significant difference (P > 0.05) between the SlALcEW and StAEW treatments efficacy. Comparing treated samples to untreated controls showed that SlALcEW and StAEW treatments extended the shelf life of chicken meat at different temperatures with marginal changes of sensory quality. Although SlALcEW and StAEW treatments showed similar antimicrobial effects but SlALcEW was more beneficial in practical application for its semineutral pH and low chlorine content. PRACTICAL APPLICATION: Food safety issues have led to development of new sanitizers to eliminate spoilage and pathogenic organisms in food. This study provides the foundation for further application of slightly acidic low concentration electrolyzed water (SlALcEW) as a sanitizing agent in meat industry. SlALcEW can be produced on site on demand and no chemicals are necessary except NaCl solution. It does not leave any residue in food due to low chlorine concentration and it is safe to handle for its semineutral pH.     

Effect of acidified sodium chlorite, chlorine, and acidic electrolyzed water on Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes inoculated onto leafy greens

Recent foodborne outbreaks implicating spinach and lettuce have increased consumer concerns regarding the safety of fresh produce. While the most common commercial antimicrobial intervention for fresh produce is wash water containing 50 to 200 ppm chlorine, this study compares the effectiveness of acidified sodium chlorite, chlorine, and acidic electrolyzed water for inactivating Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes inoculated onto leafy greens. Fresh mixed greens were left uninoculated or inoculated with approximately 6 log CFU/g of E. coli O157:H7, Salmonella, and L. monocytogenes and treated by immersion for 60 or 90 s in different wash solutions (1:150, wt/vol), including 50 ppm of chlorine solution acidified to pH 6.5, acidic electrolyzed water (pH 2.1 +/- 0.2, oxygen reduction potential of 1,100 mV, 30 to 35 ppm of free chlorine), and acidified sodium chlorite (1,200 ppm, pH 2.5). Samples were neutralized and homogenized. Bacterial survival was determined by standard spread plating on selective media. Each test case (organism x treatment x time) was replicated twice with five samples per replicate. There was no difference (P > or = 0.05) in the time of immersion on the antimicrobial effectiveness of the treatments. Furthermore, there was no difference (P > or = 0.05) in survival of the three organisms regardless of treatment or time. Acidified sodium chlorite, resulted in reductions in populations of 3 to 3.8 log CFU/g and was more effective than chlorinated water (2.1 to 2.8 log CFU/g reduction). These results provide the produce industry with important information to assist in selection of effective antimicrobial strategies.