对肉,鱼类罐头商业无菌检验的探讨

对５９种肉、鱼类罐头进行商业无菌检验。１２种样品胖听试验阳性，其中４种培养试验阳性。对所有罐进行接种培养，胖听罐与未胖听罐的接种培养阳性率有显著性差异。胖听罐的ｐＨ值与同批未胖听罐的ｐＨ值无显著性差异。     

对罐头食品商业无菌检验方法的体会

“罐头食品商业无菌的检验”(GB4798.26—89)已于1990年5月实施,新标准是将罐头感官检验、PH 测定以及进一步涂片镜检结果进行综合判断,必要时通过接种培养来确证有无微生物增殖以判定是否符合商业无菌要求。采用商业无菌检验,具有快速、经济、简便的特点,符合国际趋势,对内销和出口罐头都适用。商业无菌,是指罐头食品经过适度的热杀菌之后,不含有致病的微生物,也不含有在     

食用菌罐头商业无菌BacT/ALERT3D系统快速检测方法的研究

目的:探索和研究一种快速的罐头商业无菌检验方法。方法:对BacT/ALERT 3D系统在罐头商业无菌检验中的特异性、灵敏度和适用性进行评估,建立了罐头商业无菌仪器检验方法并与传统罐头商业无菌检验方法进行比较。结果:表明该方法检测结果可靠,简便、快速、灵敏,全部检测过程可在3d内完成。结论:BacT/ALERT 3D微生物检测系统适用于食用菌罐头商业无菌的检测。     

罐头汤汁加热装置

造成罐头成品出厂前出现的物理性胀罐(胖听)的主要原因之一是密封后罐内低真空或无真空。在生产实际中可用合理提高密封时罐头中心温度的方法来提高密封后罐内真空度。提高密封时的罐头汤汁温度可直接提高罐内中心温度。本文介绍一种实用的提高罐头     

罐藏食品酸败变质的预测试验

罐藏食品的加工最后一道工序,是杀菌冷却,为了保持各种食品的色、香、味和组织结构的固有特点,只能采用商业性杀茵。所以罐头内不是绝对无菌的。加以罐头密闭如不严,或冷却水内含有细菌,二次污染的可能性,在所难免。因此,成品检验,往往检出一些腐败性微生物,甚至能检出为数不多的致病菌。一般的惯例是,凡是成品中未检出致病性微生物,即使检出多量的腐败性微生物,而罐头内容物未酸败变质,则毫无例外的放行,出厂销售。因此,罐头在仓贮运售中,因环境因素的变化,罐头内的这些腐败性微生物大量生长繁殖,使内容物酸败变质,有一部分罐头形成胖听,成为废品。如果将这些罐头投放到市场或销售到国外,而发生酸败或胖听,造成的不良影响,是无法估计的。这种事例,屡见不鲜。1983年,就四川省几个生产出口罐头厂,肉类罐头检样11,908听,长菌者566听,占检样数的4．75%。水果罐头检样4,614听,长菌者511听,占检样数的11．07%。蔬菜罐头检样37,000听,长菌者2,658听,占检样数的7．15%。三者平均长菌率为6．95%。该年出口罐头,运往口岸(上海),肉类罐头8,990石吨,水果罐头4,812吨,蔬菜罐头36,882,8吨,在口岸复查,仅胖听罐头一项,就分别检出13．07吨,2．237吨,12．264吨,共计57.55吨,胖听率平均为0．17%。对比之下,成品中检出菌的     

原汁猪肉商业无菌检验及其看法

商业无菌指罐头食品经过适度的杀菌后不含有致病性微生物,也不含有在通常温度下能在其中繁殖的非致病性微生物。对原汁猪肉的商业无菌检验结果说明:在正常生产条件下,该产品是商业无菌的,保温库无需对其保温,这对工厂节能降耗、降低生产成本,无疑是一种福音。由卫生部批准的国际罐头食品商业无菌检验于1990年5月1日正式实施。一、材料与方法空听采用高频焊罐,214涂料,962罐型,肉源为四川万县。按班抽样,每杀菌锅抽取二罐,一般一天为一检验批,由检验员在罐头上标明杀菌     

L—74法检验番茄酱、黄桃、杨梅、桔子等水果罐头中的微生物

目前,酸性罐头的微生物检验方法与低酸性罐头一样都采用轻工业部部颁标准的方法,试验证明,部颁标准方法不适用于酸性罐头的微生物检验,而酸性水果罐头应改用新的方法——L—74法来检验微生物。 部颁标准中指出,罐头的微生物检验方法均采用常规接种法,即以无菌手续进行接种,每罐接种缓冲葡萄糖肉汤培养基二支试     

在罐头商业无菌检测中的应用

罐头食品的微生物学检验长期以来都用作罐头商业无菌检验,即通过将样品保温观察至少5—10天后,再做内容物感官检查、测定pH和显微镜检查,以确定罐头食品中有无细菌繁殖。包括我国的CB／T4789．26—2003《罐头食品商业无菌的检验》标准、联合国粮农组织（FAO）的《罐头食品商业无菌常规检验法》、美国FDA和AOAc的方法,对罐头食品的微生物学检验都采用这种商业无菌检验法。     

平酸菌

一、引言 早在1897年Prescott和Underwood评论过甜玉米罐头酸败的问题,他们把罐头酸败分胖听和不胖听两类(不胖听的酸败就是现在所说的平酸腐败)。他们还作了如下的报告:他们把某一工厂同一天生产的甜玉米罐头,一部分运到美国北部,一部分运到美国南部。结果运往南部的罐头发生了腐败,他们认为这是由于甜玉米罐头中已经有平酸菌的芽孢存在,当罐头     

罐头杀菌用变色纸

<正> 随着我国人民生活水平的不断提高,对罐头食品的消费也日趋增加,为了提高产品质量,并保证正常产品的生产,做到罐头生产各工序的科学管理,是目前我们罐头行业的重要课题。 对于罐头的杀菌,过去有的厂曾发生过同一种规格的产品连续杀菌2～3次的事故,如同一笼的桔子罐头因为连续多次杀菌造成汤汁发色,有焦糖味,桔肉有明显的苦味:也发生过未杀菌的罐头被送至保温库,后来造成罐头胖听,爆炸,甚至椿脚倒塌的现象。为避免这些     

D-alanine in Fruit Juices: A Molecular Marker of Bacterial Activity, Heat Treatments and Shelf-life

Apple, grapefruit, orange, peach, pear, pineapple and other commercial juice samples were investigated by GC (chiral phase) and HPLC (chiral eluent) to detect D-amino acids as molecular markers of bacterial activity, heat treatments, and shelf life. The development of D-amino acids was followed in grapefruit juice samples inoculated with bacteria (Lactobacillus plantarun), or yeasts (Saccharomyces cereviae). Significant amounts of free D-alanine were found only in juices affected by bacterial contamination. The content of D-alanine was not dependent upon pasteurization or sterilization treatments and did not change during the shelf-life of the products. D-alanine may be considered as a marker of bacterial contamination occurring before or during juice processing.     

灰树花功能性发酵乳饮料生产工艺的探讨

本文将脱脂乳和灰树花为原料提取的菌汁相混合,经杀菌后接种双歧杆菌与普通乳酸菌发酵、再经调配后制成功能性乳饮料,通过各项实验确定出最佳工艺条件及配方。     

HlGt-i TEMPERATURE-SHORT TIME (HTST) PROCESSING OF SUSPENSIONS CONTAINING BACTERIAL SPORES

HTST sterilization of nutrient broth containing particles inoculated with B. subtilis 5230 spores was evaluated. The particles were tight rolls of chromatography paper 12.7 mm long by 7.64 mm in diam. Presence of these particles increased the time needed to sterilize the broth. These results are quantitatively presented as a protection ratio. For nutrient broth containing paper rolls, the protection ratio was of no concern at a processing temperature of 240° F, began to become important at 250° F and became the dominant factor at 260° F and above. It is thus established that the time of a HTST process of liquids containing particles differs significantly from HTST processing of clear liquids. For example, this difference should apply to commercial HTST processing of meat in a gravy stew or dumplings in a chicken soup as contrasted with consommes or to fermentation mashes as compared to fermentation broths.     

类胡萝卜素降解对枸杞酒特征香气的影响

为探究类胡萝卜素降解后产生的降异戊二烯类化合物对枸杞酒特征香气的影响,采用一株可降解类胡萝卜素的库特氏菌进行实验。分别在枸杞渣中接种库特氏菌,枸杞清汁中接入工业酿酒酵母,发酵结束后混合;在枸杞汁中加入库特氏菌酶制剂,辅助工业酿酒酵母发酵;将高压灭菌的枸杞渣加入枸杞清汁后接种工业酿酒酵母发酵,并以正常发酵工艺酿制的枸杞酒作为对照。采用顶空固相微萃取及气相色谱质谱联用（GC-MS）法,对枸杞酒香气成分进行检测,并通过感官评分法评价3种降解类胡萝卜素方式对枸杞酒香气的影响。结果表明,库特氏菌酶制剂辅助发酵组枸杞酒香气和口感均为最佳,高压灭菌后发酵组澄清度最好。因此,在枸杞酒酿造过程中,可以采用库特氏菌酶制剂对枸杞汁进行降解处理,在此之前对枸杞渣可适度配合使用高压灭菌,从而改进枸杞酒的酿造工艺,提升枸杞酒香气。     

A robotic DNA purification protocol and real-time PCR for the detection of Campylobacter jejuni in foods

Primers designed to amplify a Campylobacter jejuni cadF gene sequence were used in an SYBR Green I real-time PCR assay as an alternative to conventional bacteriological methods for the rapid detection of C. jejuni in foods. Twenty-five grams of chicken skin (breast and thigh) was contaminated by adding approximately 1, 10, or 50 CFU of C. jejuni ATCC 35560. Twenty-five grams of pork and 25-ml aliquots of milk were also inoculated with 1 and 10 CFU of the pathogen. The samples were incubated in Bolton broth for different periods at 37 and 42 degrees C under microaerophilic conditions. Using a commercial robotic DNA purification system, DNA was extracted and purified from 1-ml aliquots of the enrichment cultures before and after centrifugation of the 250-ml enrichment broth at 15,900 x g for 10 min at 4 degrees C. The DNA was used as the template in a real-time PCR assay. C. jejuni was detected after 12 h of enrichment from samples inoculated with about 50 CFU/25-g sample. After centrifugation, an enrichment step of 8 h was sufficient to allow detection of pathogen in samples inoculated with 10 CFU/25 g. However, 24 h of enrichment was necessary to detect pathogen in samples inoculated with approximately 1 CFU/25 g. The real-time PCR protocol developed in this study significantly reduced the detection time of C. jejuni in foods.     

响应面法优化草莓鲜榨汁紫外杀菌工艺

以草莓鲜榨汁为原材料,进行紫外线杀菌,研究草莓鲜榨汁厚度、紫外线照射距离和紫外线照射时间对菌落总数、霉菌和酵母菌总数杀菌率的影响。利用响应面分析法确定紫外线杀菌的最佳工艺参数为果汁厚度0.7?mm、照射距离8.0?cm、照射时间62?min,得到实际杀菌率为99.24%。在最佳工艺条件下对草莓鲜榨汁进行紫外杀菌,并与巴氏杀菌比较对草莓鲜榨汁品质指标的影响。结果表明：紫外线杀菌可以提高草莓鲜榨汁中花色苷和总酚的含量;有利于减缓草莓鲜榨汁中可滴定酸含量的降低,但对可溶性固形物无显著影响;另外紫外线杀菌降低了草莓鲜榨汁中VC的含量,但是与巴氏杀菌相比较,VC损失率减少了28.7%。这说明紫外线杀菌可以在达到商业无菌的前提下,维持草莓鲜榨汁中的营养成分。     

Proteolytic activity of molds and their metabiotic association with Salmonella in a model system

The aim of this study was to investigate the proteolytic ability of some strains of aspergilli, fusaria, and penicillia and the metabiotic effect of Fusarium oxysporum and Penicillium expansum on Salmonella. The proteolytic activity of the target molds was determined on tomato juice agar and tomato juice, whereas the metabiotic effect of F. oxysporum and P. expansum on Salmonella was assessed in a model system consisting of tryptone soy broth with different amounts of tomato juice added. Fusaria, some aspergilli, and one strain of penicillium showed a proteolytic activity on tomato juice agar. In addition, Salmonella survival was enhanced in tryptone soy broth plus 20 or 50% tomato juice in the model system previously inoculated with F. oxysporum.     

果汁饮品杀菌工艺过程控制系统设计

为延长果汁饮品保存日期、保证果汁食品质量,需要对果汁进行有效灭菌,其中通过高温加热方式可有效对果汁进行杀菌。杀菌工艺中温度变化又具有非线性、时变性等特点,传统PID控制方法并不能满足温度精确高效调节的要求,为此设计一款基于模糊PID的果汁饮品杀菌控制算法。介绍果汁杀菌工艺流程,在传统PID控制器中引入模糊控制理论,通过模糊控制方法实现PID参数的在线自动调节。仿真结果表明,该控制系统能够快速实现温度的收敛,在尽可能短的时间内达到目标温度,且达到目标温度后温度波动较小,该温度控制方法可有效提高杀菌效果,提升果汁品质。     

UHT杀菌对绿茶饮料风味的影响研究

研究了UHT杀菌对绿茶饮料风味的影响，通过绿茶饮料在UHT杀菌前、后香气成分的定性．定量分析，说明UHT杀菌在杀死绿茶饮料中的有害及腐败微生物时．不仅可以极大程度地保留产品中的营养成分和风味成分，同时还增加了绿茶饮料的甜香成分．     

不同杀菌方式对桑葚原汁品质的影响

以桑葚原汁为材料,对比分析了巴氏杀菌、超高温瞬时杀菌（ultra high temperature treated,UHT）以及静态超高压杀菌（ultra high hydrostatic pressure,UHHP）3 种不同的杀菌处理对桑葚原汁的微生物、品质和香气成分的影响。结果表明：3 种杀菌方式处理的桑葚原汁均符合GB 19297-2003《果、蔬汁饮料卫生标准》要求,UHT杀菌更彻底,未有微生物检出。与未杀菌桑葚原汁相比,可溶性固形物、总糖含量经巴氏杀菌和UHT处理后都出现了较显著下降趋势（P＜0.05）;UHHP处理对花色苷含量影响最大;总酚含量、类黄酮含量以及抗氧化能力经过不同杀菌处理后表现出不同程度的下降,UHHP处理影响最小。采用固相微萃取-气相色谱-质谱联用技术对未杀菌桑葚原汁及巴氏杀菌、UHT和UHHP桑葚原汁香气成分进行分析,分别鉴定出52、42、44、49 种挥发性香气成分。UHHP桑葚原汁各主要香气成分与未杀菌桑葚原汁最为接近。UHHP技术不仅具有良好的杀菌效果,而且能较好的保持桑葚原汁的品质。