牦牛屠宰过程中菌落总数和大肠菌群污染状况的分析

为了掌握牦牛屠宰过程中菌落总数和大肠菌群的污染状况,本实验对甘肃玛曲某牦牛屠宰场在牦牛屠宰过程中的屠宰前、屠宰中和分割后三个阶段以及牦牛胴体等14个采样点进行采样,进行菌落总数和大肠菌群的测定。研究发现,屠宰前的各采样点中,菌落总数在5.45logCFU/g以上,大肠菌群在3.25logCFU/g以上;屠宰中的各采样点中,菌落总数在3.37logCFU/cm2以上,大肠菌群在1.63logMPN/100cm2以上;在分割后的各采样点中,菌落总数在3.68logCFU/cm2以上,大肠菌群在1.74logMPN/100cm2以上;在胴体的剥皮、劈半和分割三个时期中,分割后的菌落总数(3.49logCFU/cm2)和大肠菌群(1.61 logMPN/100cm2)污染最严重,剥皮后的菌落总数(2.47logCFU/cm2)和大肠菌群(1.53logMPN/100cm2)污染最小。结果表明,屠宰前环境污染最严重,胴体随着剥皮、劈半和分割的进行,菌落总数显著增加,分割后胴体的大肠菌群显著高于剥皮和劈半。     

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。     

传统清真屠宰厂屠宰过程中微生物变化

为了研究传统清真屠宰厂屠宰过程中微生物变化,寻找微生物污染控制点,实验主要对屠宰过程中各环节菌落总数和大肠菌群指标变化进行检测。检测结果显示,在屠宰过程中微生物污染源来自于多方面,但最主要的来源是工作人员的手部、刀具以及操作台,而在屠宰的各个环节中最严重的污染源来自修割处。胴体经过冲淋后表面菌落总数和大肠菌群均有明显减少,冲淋是减少牛胴体表面微生物污染的重要环节。对工作人员手部与器具的消毒、冲淋和降低屠宰过程中各主要环节的温度都可以有效的控制微生物污染,对提高牛肉的品质有重要意义。     

鸡肉调理制品生产过程中污染微生物的调查研究

针对目前鸡肉调理制品货架期短的问题,对鸡肉调理制品在生产过程中的微生物污染状况进行调研。以菌落总数为测定指标探讨肉鸡屠宰分割生产线和鸡肉调理制品生产线及各车间生产环境的微生物污染状况。结果表明：屠宰车间环境污染严重,分割车间环境较好,屠宰结束后的鸡胴体和其分割产品菌落总数在2.12～3.95(lg(CFU/cm2))范围内,处在国标规定范围内,属于合格产品;肉鸡副产品(内脏)菌落总数达到3.87～4.31(lg(CFU/cm2)),显著高于分割产品;鸡肉调理制品生产环境存在严重微生物污染问题,处在不可接受水平内;鸡肉调理制品生产存在严重的微生物污染问题,鸡肉丸生产过程中菌落总数高达4.27～5.55(lg(CFU/g)),而鸡柳菌落总数则达到4.32～5.78(lg(CFU/g)),终产品属于超标产品。     

肉牛屠宰过程中胴体表面及接触环境污染情况分析

为研究肉牛屠宰场屠宰过程中牛胴体表面污染及接触环境污染变化情况,选取某牛屠宰场采集样品共计322 份,分别在剥皮扯皮、去内脏、修整称质量、冲洗及排酸环节对牛胴体后腿、背部、胸部、前腿及颈部以及屠宰前后的工人手部及刀具进行采样,测定菌落总数、乳酸菌、大肠菌群、金黄色葡萄球菌及假单胞菌的污染情况。结果表明：胴体表面污染情况总体呈现先上升后下降的趋势,修整称质量环节污染最为严重,菌落总数可达到2.82（lg（CFU/cm2））;胸部为屠宰过程中污染最严重的部位,平均菌落总数可达到2.10（lg（CFU/cm2））;屠宰空气在冲洗时污染最为严重,空气沉降菌落总数高达271.33 CFU/皿;屠宰工人的手部及刀具也是胴体污染的主要来源。     

肉鸡屠宰加工过程中胴体微生物污染分析及不同冲淋条件对胴体减菌的影响

测定肉鸡在屠宰加工过程中脱毛后、掏内脏后、胴体清洗后、预冷后、分割后、速冻后胴体表面的菌落总数、大肠菌群、肠球菌数量以及检测产品的金黄色葡萄球菌、沙门氏菌;通过对不同浓度乳酸、不同温度热水、不同冲淋时间进行均匀设计分组,冲淋处理胴体清洗前的肉鸡胴体,测定其菌落总数。肉鸡在整个屠宰生产链上胴体污染的菌落总数、大肠菌群和肠球菌数分别为4.56⁵.74、2.665.74、2.66⁴.81、2.014.81、2.01³.57(log10CFU/cm2)。肉鸡产品的菌落总数4.57(log10CFU/cm2)符合GB16869-2005鲜、冻禽产品标准,大肠菌群3.50(log10 CFU/cm2)、金黄色葡萄球菌、沙门氏菌的检出率分别为37.25%、12.75%,不符合标准,肠球菌没有限量标准,但产品的肠球菌数(2.53(log10CFU/cm2))较高;对肉鸡胴体表面减菌的适宜条件为乳酸浓度1.5%、热水温度50℃、冲淋时间15 s,可减少菌落总数1.998(log10CFU/cm2)。肉鸡屠宰过程中胴体微生物污染较严重,存在致病菌污染,乳酸结合热水冲淋可显著减少肉鸡胴体表面的菌落总数。     

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。     

冷鲜肉生产过程中微生物污染分析及控制对策

冷鲜肉由于营养丰富且水分活度高,在生产加工过程中极易受微生物的污染而腐败变质。检测分析生猪屠宰和生产分割线上肉样的微生物污染状况,并对其污染的控制提出了应对措施。试验采集冷鲜肉加工环节中的不同肉品样本和器具样本,按照国家标准方法对其中细菌总数和大肠菌群指标进行检测。研究结果揭示生产线上不同分割肉品微生物卫生指标的菌落总数和大肠菌群均没有超过国家标准限量,菌落总数平均为103cfu/g,大肠菌群值在102~103MPN/100g之间。猪内脏肉样包括猪肺、猪心和猪肝,菌落总数在103~104cfu/g之间,大肠菌群值为102MPN/100g,均明显低于分割肉品的污染量。烫毛后的淋洗过程是清除胴体表面附着微生物的一个关键环节,通过淋洗环节猪胴体表面菌落总数和大肠菌群分别减少了17.4%和41.5%。生产器具中污染状况最为严重是案板,其菌落总数平均为1.5×103cfu/cm2,其次是传送带,最后是刀具。不同生产批次肉品由于工序、器具和人员等不稳定因素,微生物污染状况差异较大。     

屠宰过程中猪胴体表面及环境的细菌菌相分析

应用传统培养方法结合高通量测序技术分析屠宰分割过程中猪胴体表面微生物污染情况，并对屠宰车间刀具和分割车间接触面进行细菌菌落计数，以确定屠宰分割过程中的关键污染环节。结果表明：测序共得到881 458 个有效序列，864 个可操作分类单元，样品共注释到了22 门、33 纲、79 目、162 科、382 属和613 种的微生物信息。变形菌门（Proteobacteria）、拟杆菌门（Bacteroidota）和厚壁菌门（Firmicutes）为优势菌门，不动杆菌属（Acinetobacter）和气单胞菌属（Aeromonas）为主要的优势菌属。屠宰分割过程中群落多样性的排序为放血＞脱毛＞分割＞开膛＞冲淋＞冷却，冷却环节胴体表面的微生物多样性最低，分割后有所增加，表明分割是关键污染环节。传统微生物计数与测序的结果一致，从脱毛到冷却环节，猪胴体表面各类微生物数量呈下降趋势，分割后显著上升；分割车间各接触面菌落总数平均为6.11（lg（CFU/cm2）），高于屠宰车间刀具（平均为4.86（lg（CFU/cm2））），表明分割车间各接触面是关键污染源，进一步证明猪胴体分割环节为关键污染环节。     

鸡精调味料加工过程中微生物检测及安全控制

为提高鸡精调味品卫生质量,根据生产工艺特点分别对鸡精生产原辅料、加工流程及主要加工设备进行了微生物检测。食用玉米淀粉和葱姜混合物是鸡精生产原辅料中的主要微生物来源,水分含量是直接影响玉米淀粉微生物污染的主要因素,当水分含量10%时,100 g玉米淀粉大肠菌群70 MPN;葱姜混合物经30%质量分数的食用盐处理后可控制微生物的数量。鸡精生产工序过程中的搅拌后、造粒前后及流化干燥前微生物污染严重,其中搅拌后菌落总数最高,为1.2×104CFU/g,造粒前大肠菌群最高,为167 MPN/100g,搅拌和造粒是鸡精生产过程中的关键控制环节。另外,造粒机筛网及侧槽的菌落总数达到908 CFU/cm2,高于食品车间卫生标准,表明造粒岗位是鸡精生产的一个关键控制点。     

A survey of microbial contamination of food contact surfaces at broiler slaughter plants in Taiwan

Microbial contamination levels at broiler slaughter plants were investigated at three major slaughter plants in Taiwan during the summer and winter. The microbial contamination levels in chicken carcasses and on food contact surfaces were examined using the swab method. The results indicated that the bacterial counts were affected by the slaughter processing plant, processes, and season (P < 0.05). The bacterial counts on food contact surfaces of the equipment before operation were not significantly lower than those after processing. Regardless of the bacterial type, bacterial counts of chicken carcasses generally decreased from the scalding step to the washing step before evisceration and then increased. The cleaning procedures for food contact surfaces should be evaluated, and special attention should be given to utensils used during processing, such as gloves, baskets, and hand tools.     

Effect of prechill fecal contamination on numbers of bacteria recovered from broiler chicken carcasses before and after immersion chilling

Paired carcass halves were used to test whether fecal contamination of skin during processing of broiler chickens can be detected by increased bacterial counts in samples taken before and after immersion chilling. In each of three trials, six freshly defeathered and eviscerated carcasses were cut in half, and a rectangle (3 by 5 cm) was marked with dots of ink on the breast skin of each half. One half of each pair was chosen randomly, and 0.1 g of freshly collected feces was spread over the rectangle with a spatula. After 10 min, both halves were sprayed with tap water for 10 to 15 s until feces could no longer be seen in the marked area. Both halves were sampled with a 1-min carcass rinse and were then put in a paddle chiller with other eviscerated carcasses for 45 min to simulate industrial immersion chilling. Immediately after chilling, each carcass half was subjected to another 1-min rinse, after which the skin within the rectangle was aseptically removed from the carcass halves and stomached. Rinses of fecally contaminated halves had significantly higher Enterobacteriaceae immediately before chilling, but there were no differences in coliform and Escherichia coli counts. After chilling, there were no differences in Enterobacteriaceae, coliform, and E. coli counts in rinse or skin samples from the paired carcass halves. Correlations were generally poor between counts in rinse and skin samples but were significant between prechill and postchill rinses for both control and fecally contaminated halves. Correlations were also significant between counts in rinses of control and contaminated halves of the same carcass after chilling. Bacterial counts in postchill carcass rinses did not indicate that fecal contamination occurred before chilling.     

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.     

肉鸡屠宰加工中减菌处理前后细菌菌相分析

基于16S rDNA V6～V8可变区的聚合酶链式反应-变性梯度凝胶电泳（polymerase chain reaction-denaturinggradient gel electrophoresis,PCR-DGGE）技术分析肉鸡屠宰加工过程中减菌处理前后胴体或产品细菌多样性。在预冷环节前采用50 ℃、1.5%乳酸溶液对肉鸡胴体冲淋15 s进行减菌处理,采集屠宰加工环节中减菌处理前后的胴体或分割产品表面样品,提取样品中的细菌总DNA,通过16S rDNA V6～V8可变区的PCR扩增,变性梯度凝胶电泳,对PCR扩增片段割胶回收、克隆测序分析减菌前后细菌菌相变化。结果表明,减菌前,胴体清洗环节DGGE条带的数量最多、亮度最强,细菌污染最严重,其次是分割环节,而预冷环节细菌种类及数量最少,污染程度最低;减菌后,各屠宰加工环节细菌种类与数量较减菌前均有所减少,其中胴体清洗环节与分割环节细菌的种类与数量减少量最多,预冷环节细菌的种类及数量最少,不同屠宰加工环节细菌种类并不完全一致;乳杆菌属细菌在整个肉鸡屠宰加工过程中均有出现,与肠杆菌科和假单胞菌属细菌为肉鸡屠宰加工过程中的优势腐败菌。     

The development of a 'clean sheep policy' in compliance with the new Hygiene Regulation (EC) 853/2004 (Hygiene 2)

The aim of this research was to identify the risk factors associated with the transfer of bacterial contamination from the fleece to the ovine carcass thereby providing the scientific basis for the development and validation of a clean sheep policy. Two hundred sheep in lairage were graded into five categories each consisting of 40 sheep. The categories were as follows; (A) clean and dry; (B) clean and wet; (C) dirty and dry; (D) dirty and wet and (E) visible dags (dung-clotted tufts of wool) categorized by the chief veterinary inspector at the slaughter plant based on the visual inspection of the hygienic status of the fleece. Microbiological evaluations of the carcasses were conducted using swab sampling methods. Total viable counts (TVCs), Enterobacteriaceae and coliform counts were obtained from 40 animals per category at four separate sites (brisket, shoulder, flank and rump) immediately after pelt removal. Statistical analysis of TVC data obtained from the carcass indicated that the dirt level of the fleece had a significant effect on contamination levels when the fleece was dry. Enterobacteriaceae and coliform counts suggest that dirt was a contributing risk factor regardless of wetness or dryness of the animal. The clean sheep policy should therefore differentiate between clean and dirty sheep and mandate additional hygiene measures for the latter.     

The effect of abattoir design on aerial contamination levels and the relationship between aerial and carcass contamination levels in two Irish beef abattoirs

This study investigated the relationship between aerial and beef carcass contamination and examined the effect of abattoir design and time of slaughter on the aerobiology of slaughter operations in two commercial beef abattoirs. A dual head impaction air sampler and swab samples taken from 100 cm² of the brisket of beef carcasses, were used to examine Total Viable, Psychrotrophic, Enterobacteriaceae and Pseudomonad numbers. In Abattoir A, with a straight-line single-floor design, airborne bacterial numbers were generally lower in the “clean” than in the “dirty” area of the plant. In Abattoir B, which had a serpentine two-floor design, this trend was generally reversed. Both abattoirs displayed a similar pattern in airborne counts over the production day, with numbers generally being lower before slaughter, than in the morning and afternoon. Correlations between aerial and carcass contamination for each of the bacterial groups on the slaughter line in Abattoirs A and B were poor. The data suggest that it is difficult to make a definitive evaluation of the relationship between aerial and carcass contamination levels. Methods currently used to determine the relationship between aerial and carcass contamination need to be reconsidered.     

Determination of the principal points of product contamination during beef carcass dressing processes in Northern Ireland

To determine the principal points of microbial contamination of carcasses during beef carcass dressing in Northern Ireland, 190 carcasses were sampled by swabbing 1,000 cm2 of the brisket. A detailed survey of one abattoir was initially conducted, with sampling of a total of 100 carcasses immediately after hide removal (H), after carcass splitting (S), and immediately after washing (W) before dispatch to the chiller. The total bacterial counts after incubation at both 22 and 37 degrees C indicated that there was no significant increase in the numbers of bacteria after the first sampling point, H (P > 0.05). To determine whether this was the case in the majority of Northern Ireland abattoirs, 15 carcasses were then sampled at each of an additional six abattoirs, at points H and W only. Total bacterial counts were significantly higher (P < 0.05) at H than at W, indicating that hide pulling was the major point of bacterial contamination of beef carcasses and hence a critical control point for the final microbiological quality of the carcasses. Mean counts of Enterobacteriaceae at both incubation temperatures were very low (< 10 CFU/cm2) but were higher at W than at H, probably indicating that washing was redistributing bacteria from the posterior to the anterior region.     

Efficacy of hypobromous acid as a hide-on carcass antimicrobial intervention

Escherichia coli O157:H7 and Salmonella on cattle hides at slaughter are the main source of beef carcass contamination by these foodborne pathogens during processing. Hypobromous acid (HOBr) has been approved for various applications in meat processing, but the efficacy of HOBr as a hide antimicrobial has not been determined. In this study, the antimicrobial properties of HOBr were determined by spraying cattle hides at either of two concentrations, 220 or 500 ppm. Treatment of hides with 220 ppm of HOBr reduced the prevalence of E. coli O157:H7 on hides from 25.3 to 10.1% (P < 0.05) and reduced the prevalence of Salmonella from 28.3 to 7.1% (P < 0.05). Treatment of hides with 500 ppm of HOBr reduced (P < 0.05) the prevalence of E. coli O157:H7 on hides from 21.2 to 10.1% and the prevalence of Salmonella from 33.3 to 8.1%. The application of 220 ppm of HOBr reduced (P < 0.05) aerobic plate counts, total coliform counts, and E. coli counts on hides by 2.2 log CFU/ 100 cm(2). The use of 500 ppm of HOBr resulted in reductions (P < 0.05) of aerobic plate counts, total coliform counts, and E. coli counts by 3.3, 3.7, and 3.8 log CFU/100 cm(2), respectively, demonstrating that the use of higher concentrations of HOBr on hides resulted in additional antimicrobial activity. These results indicate that the adoption of a HOBr hide wash will reduce hide concentrations of spoilage bacteria and pathogen prevalence, resulting in a lower risk of carcass contamination.