不同工艺条件对猪胴体和冷却猪肉微生物去污染效果的影响

本文调查了冷却猪肉生产企业现有生产工艺下微生物污染的状况;研究了对现有生产工序(冲淋工序、冷却工序)采取新的工艺处理,包括水冲洗、乳酸喷淋、冷分割以及联合处理对猪胴体和冷却猪肉微生物去污染的效果.结果表明现有生产工艺下,冷却猪肉微生物污染随季节发生显著的变化,且达不到HACCP体系微生物控制要求;水冲淋、乳酸喷淋、冷分割单独处理或联合处理,均有显著的微生物去污染效果.如果热分割,劈半后冲洗1分钟,乳酸喷淋1分钟微生物去污染效果显著;冷却猪肉可基本达到HACCP微生物控制要求.如果冷分割,劈半后冲洗1分钟,冷却24小时,再冷分割效果较好,冷却猪肉可基本达到HACCP微生物控制要求;若劈半后冲洗1分钟,乳酸喷淋1分钟,冷却24小时可完全达到HACCP微生物控制要求.     

基于微生物危害的冷却猪肉加工过程关键控制点分析与控制

应用危害分析和关键控制点(HACCP)原理,测试冷却猪肉加工过程中车间环境、加工工序、操作人员、器具以及肉表面的微生物数量分布,获得重要污染环节为刺杀放血、开膛去脏、冷却排酸、分割和包装;其中分割剔骨环节受污染最严重。通过分析加工过程微生物的分布状况,建立基于微生物危害的冷却猪肉加工过程关键控制点(CCP),重点改善卫生管理,使产品初始菌数降至最低,提升质量安全。     

HACCP体系在冷却分割猪肉生产中的应用

探讨了HACCP原理在冷却分割猪肉生产及安全控制中的实施和应用。通过对冷却分割猪肉生产过程的危害分析,确定了生猪收购、电击昏、冷却、冲洗、分割、包装、冷藏、运输等8个关键控制点。并根据HACCP原理,分别制定了各个关键控制点的关键限值和监控措施。结果表明,通过在冷却分割猪肉中实施HACCP体系,可以有效的将危害降低到可接受水平,从而确保肉的品质与安全。     

猪肉冷链加工与物流微生物危害分析与控制

基于微生物危害分析,测试冷却分割猪肉冷链加工与物流过程的微生物数量和温度分布,明确关键污染环节和物流过程温度波动,建立关键控制点及其控制措施,制定冷却猪肉冷链加工与物流HACCP计划,提出重点改善卫生管理和温度监控措施,使产品微生物数量控制在可接受水平,确保加工流通过程产品质量安全。     

肉牛屠宰工序微生物污染状况分析和喷淋减菌技术

以减少冷却后牛胴体表面的微生物数量为目标,在企业实际生产条件下,以菌落总数为指标分析屠宰过程中各工序胴体表面的微生物变化状况,探讨不同喷淋方式的减菌效果。结果表明,屠宰工序中初始剥皮操作对胴体造成的污染最严重,其次为去脏工序。高压清水清洗对全胴体的减菌量为0.62(log10CFU/cm2);2%的乳酸喷淋对胸口部位菌落总数的减少量为1.06(log10CFU/cm2)。采用2%的乳酸喷淋可以有效减少肉牛屠宰过程中的胴体污染。     

冷却猪肉分割过程中微生物污染状况的研究

对冷却猪肉在分割过程中的主要接触物、分割肉本身的微生物污染和增殖情况进行研究。结果表明:分割过程中分割线上主要接触物的微生物数量随生产时间的延长而增加,传送带的微生物数量1h内达到1.89～2.48 lg(CFU/cm2),4h达到2.63～3.18lg(CFU/cm2);工人手、刀具、电锯和案板0.5h内微生物数量达到1.42～2.36 lg(CFU/cm2),2h达到1.84～3.08lg(CFU/cm2);初始冷却猪肉的微生物主要集中在胴体表层,在分割和精修过程中,冷却猪肉与污染物的接触,造成二次污染,不同部位分割冷却猪肉的微生物数量也不同,表面微生物数量在2.56～3.68 lg(CFU/cm2)之间,肉中微生物数量在3.18～3.97 lg(CFU/g)之间。     

不同工艺参数乳酸处理对猪肉肉色及去微生物污染的影响

目的:研究了不同工艺参数乳酸处理对猪肉肉色以及去微生物污染的影响。方法:通过对乳酸不同浓度(1.0%、1.5%、2.0%)、不同温度(35、45、55℃)、不同时间(30、45、60s)进行正交试验设计分组,浸泡处理猪肉(背最长肌),测定其红色度a*值变化;将上述两组乳酸处理工艺分别处理大肠杆菌和沙门氏菌。结果:对猪肉肉色影响不显著(p>0.05)的乳酸处理组工艺参数分别为乳酸浓度1.5%、温度45℃、时间60s和乳酸浓度2.0%、温度35℃、时间60s;乳酸浓度1.5%、温度45℃、时间60s处理与乳酸浓度2.0%、温度35℃、时间60s处理对大肠杆菌和沙门氏菌的致死效果均显著。结论:上述两组乳酸处理工艺可为冷却猪肉生产HACCP质量控制体系中乳酸喷淋减菌关键控制点关键限值的选择提供依据。     

牛肉中初始微生物来源分析

为了延长冷鲜牛肉保鲜期,减少初始腐败菌,采用菌落计数和聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)技术来分析肉牛屠宰车间空气以及相关屠宰工序中工人手、工具、冲淋水等菌相分布,确定出厂前牛肉主要污染工序和初始微生物来源。结果表明:出厂前牛肉主要携带约氏不动杆菌、巨型解酪球菌、葡萄球菌等,主要污染工序为去头蹄、分割工序,其中工人手、手套、刀、案板、镊子、手钩、传送带为主要污染源。     

夏季啤酒生产微生物污染及其控制

对啤酒厂来说,夏季不仅生产任务艰巨,也是一场微生物控制的大战。 1微生物污染途径 1）原料变质污染及糖化工序污染; 2）麦汁管道及冷却薄板清洗、杀菌不彻底; 3）麦汁充氧用无菌风及接触空间污染;     

冷却肉的加工技术及质量控制

冷却肉（猪肉）是指宰后胴体迅速进行冷却处理,使胴体温度在24小时内降为0-4℃,并在后续的分割、包装、流通和零售等过程中,始终处于0-4℃范围内的生鲜肉（猪肉）。微生物的污染是冷却肉产品质量的重要危害,因此,我们在生产加工与流通过程中实施HACCP系统监控,以确保产品的安全卫生。冷却肉的流通结合实际情况,目前采用加工厂内真空大包装,运输到超级市场后,制作成托盘保鲜小包装。     

肉牛屠宰过程中的减菌技术研究进展

为了减少冷却肉的初始菌落数,延长其货架期并提高其安全性,众多学者对畜禽胴体及冷却肉减菌技术进行了研究。因此,本文对近年来肉牛屠宰过程及冷却牛肉生产过程中应用的减菌技术研究进展进行概述,总结基于物理方法减菌的胴体修整及清水冲洗、热除菌、紫外线杀菌和低温等离子体杀菌等措施,以及基于化学方法减菌的有机酸喷淋、过氧乙酸喷淋等措施。通过比较分析每种方法的减菌效果及优缺点,初步得出清水冲洗与乳酸喷淋的复合减菌方法是既有效又经济的牛胴体减菌措施的结论。通过本文的总结和概述,期望可以为肉牛屠宰企业合理地选择减菌措施提供参考。     

MICROBIAL CHANGES ON FRESHLY SLAUGHTERED PORK CARCASSES DUE TO "HOT" LACTIC ACID DECONTAMINATION

We studied the microbial changes on fresh (still warm) pork carcasses immediately after electrostatic spraying of lactic acid solutions and during chilled storage. Lactic acid decontamination (LAD) included electrostatic spraying of hot (55C) solutions of 1% lactic acid for 90 s and 2%- and 5% lactic acid for 30 and 90 s. The treatments increased the carcass surface temperature from 22C to about 32–43C. The bactericidal activity of lactic acid killed mainly Gram-negative bacteria. Reductions in "total" psychrotrophic Gram-negative and Entero-bacteriaceae counts were found reliable indicators for the efficacy of LAD. Hot 2–5% LAD treatments achieved overall reductions in Gram-negative psychrotrophs ranging from 0.8 to more than 1.4 log₁₀ cfu per cm². Overall reductions in mesophilic Enterobacteriaceae counts ranged from approximately 1.2 to more than 1.8 log₁₀ cfu per cm². Treatments with 1% lactic acid achieved marginal 0.5–0.6 overall log₁₀ reductions in these groups of organisms. Bactericidal effects after LAD occurred during a lag period of whose duration increased with the lactic acid concentration of the spray solution. The lag lasted less than 1 day on 1% LAD, 2 days on 2% LAD and 4 days on 5% LAD meat. During these lags the meat surface pH rose from pH 2.7 to 3.2 immediately after LAD to pH 4.8 to 5.2. During aerobic chilled storage after LAD the growth of Gram-negative psychrotrophs was controlled only temporarily. These organisms became the dominant group of organisms. The practical utility of electrostatic spraying of fresh pork carcasses with hot 1–5% LAD to improve the keeping quality is questionable .     

不同屠宰工艺(剥皮和烫毛)对猪胴体表面微生物的多样性影响及关键点的控制研究

应用变性梯度凝胶电泳(Denaturinggradientgelelectrophoresis(DGGE))和经典微生物培养相结合的方法研究了剥皮和烫毛工艺中猪胴体表面污染的微生物数量和细菌多样性的变化以及3.5%乳酸处理后细菌总数和大肠菌群的变化。结果显示:不同猪胴体屠宰工艺中的微生物种类并不完全一致,微生物的污染多是由于前期的屠宰工艺引入;与剥皮工艺相比,烫毛后污染的微生物种类多,初始污染程度也较为严重;乳酸处理显著降低了剥皮工艺中的细菌总数,使出库猪胴体表面细菌总数降低到2.95logCFU/cm2,完全达到HACCP微生物的控制要求,但是没有降低烫毛工艺出库时的细菌总数,因此对不同的屠宰工艺应采取不同的关键点控制措施。     

Microbial populations on animal hides and beef carcasses at different stages of slaughter in plants employing multiple-sequential interventions for decontamination

Multiple-sequential interventions were applied commercially to reduce beef carcass contamination in eight packing plants. The study evaluated microbial populations on animal hides and changes in carcass microbial populations at various stages in the slaughtering process. Sponge swab samples yielded mean (log CFU/100 cm2) total plate counts (TPC), total coliform counts (TCC), and Escherichia coli counts (ECC) on the exterior hide in the ranges of 8.2 to 12.5, 6.0 to 7.9, and 5.5 to 7.5, respectively, while corresponding contamination levels on carcass surfaces, after hide removal but before application of any decontamination intervention, were in the ranges of 6.1 to 9.1, 3.0 to 6.0, and 2.6 to 5.3, respectively. Following the slaughtering process and application of multiple-sequential decontamination interventions that included steam vacuuming, pre-evisceration carcass washing, pre-evisceration organic acid solution rinsing, hot water carcass washing, postevisceration final carcass washing, and postevisceration organic acid solution rinsing, mean TPC, TCC, and ECC on carcass surfaces were 3.8 to 7.1, 1.5 to 3.7, and 1.0 to 3.0, respectively, while corresponding populations following a 24 to 36 h chilling period were 2.3 to 5.3, 0.9 to 1.3, and 0.9, respectively. The results support the concept of using sequential decontamination processes in beef packing plants as a means of improving the microbiological quality of beef carcasses.     

肌肽对猪肉的氧化抑制和保鲜作用

肌肽是一种具有抗氧化等功能的天然的二肽,本试验比较了肌肽对猪肉匀浆的抗氧化作用,同时比较了不同保鲜剂对冷鲜肉保藏期的延长作用。实验发现,1mmol/L肌肽标准液对猪肉匀浆中丙二醛的形成量就能起到显著的抑制作用(P<0.05),此时对体系中脂类氧化的抑制率即达到12%,5mmol/L肌肽对体系中脂类氧化的抑制率达15%,20mmol/L肌肽对体系中脂类氧化的抑制率达47%,表明不同浓度的肌肽均能对猪肉匀浆中脂类氧化起显著的抑制作用,其中随浓度的增加效果增强。与BHT和α-生育酚相比,肌肽对TBARS的抑制能力较高。肌肽可以延长冷鲜肉的保存时间,添加了肌肽的冷鲜肉保藏时间由不添加保鲜剂的9天增加到15天,其效果要优于抗坏血酸,肌肽牛肉预煮液也可以延长冷鲜肉的贮藏时间。     

胡椒提取物在冷却肉保鲜中的应用

研究胡椒提取物作为复合保鲜剂的成分在延长冷却肉货架期方面的作用。采用常压回流方法获得胡椒提取物,再以胡椒提取物、壳聚糖和乙酸为试材,对冷却肉进行贮藏保鲜,最后采用二次通用旋转组合设计法,对复合保鲜液配方成分的比例进行优选。结果表明：复合保鲜剂能明显地抑制保藏过程中微生物的生长。胡椒提取物质量分数0.95%,壳聚糖质量分数0.99%,乙酸质量分数0.80%的保鲜剂配方较好,保鲜12d后细菌总数(lg(CFU/g))为5.2214。     

In-Plant evaluation of a lactic acid treatment for reduction of bacteria on chilled beef carcasses.

The effectiveness of a lactic acid treatment consisting of spraying a 4% L-lactic acid solution (55 degrees C at source) on chilled beef carcasses to reduce bacterial populations was tested in a commercial slaughter environment. All carcasses had been treated with a proprietary decontamination treatment composed of a hot water spray followed by a lactic acid spray prior to chilling. Bacterial groups used to indicate reductions included aerobic plate count (APC), total coliform count, and Escherichia coli count, and samples were examined from the brisket, the clod, and the neck regions of 40 untreated and 40 treated carcass sides. Depending on the carcass surface region, APCs were reduced by 3.0 to 3.3 log cycles. Log coliform and E. coli counts were consistently reduced to undetectable levels. The small reductions observed for coliforms are attributable to counts on untreated carcasses already being near the lower detection limit of the counting method. The percentage of samples with detectable numbers of coliforms (positive samples) on untreated carcasses ranged from 52.5 to 92.5%, while 0.0% of the samples collected from treated carcasses contained detectable coliforms. Percent E. coli-positive samples ranged from 7.5 to 30.0% on untreated carcasses and 0.0% after treatment of carcass sides. These results indicate that a hot lactic acid spray with increased concentration and time of application may be effectively implemented for an additional decontamination treatment of chilled beef carcasses prior to fabrication.     

氧化电位水处理杀灭速冻饺子肉馅微生物

对利用氧化电位水(EOW)杀灭肉馅细菌的工艺及参数进行研究。杀菌实验结果表明,在肉水比低于1:6(m/V)的条件下,将冷鲜肉置于酸性氧化电位水(EO-A)中浸泡15min,将使所制得的肉馅中总菌落数下降3 个数量级以上,而且其杀菌效果不会受到肉中脂肪组织含量的显著影响。为充分利用EO-A,将浸泡时间控制在20min 以内并使肉水比小于1:2 可使处理后的EO-A 保持杀菌效力并可重复使用。该研究表明,利用EOW处理技术杀灭肉馅微生物在延长速冻饺子货架寿命方面具有良好应用潜力。     

亲水性单甘脂复合保鲜剂对冷却猪肉保质期及品质影响的研究

亲水性单甘脂具有良好的保水性,而250ppm Nisin+1.5%乳酸钠+1.5%乳酸,能有效抑制冷却肉中腐败菌的生长。本文分别对亲水性单甘脂、250ppm Nisin+1.5%乳酸钠+1.5%乳酸复合保鲜剂及由两者结合形成的复合防腐剂,经聚乙烯袋包装后在冷藏(0～4℃)条件下的保鲜效果进行研究,并测定细菌总数、pH值、汁液损失率、色差和感官评价等指标,结果表明,将两者结合,既能减少汁液的流失,又能延缓冷却肉中腐败菌的生长。