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如何借助仪器分析法来对食品进行检测分析作者：来源：《食品安全导刊》2020年第11期就目前食品检测分析行业的形势来看，相关食品检验检测研究机构在对食品进行检测分析的过程中仍存在较多问题。
究其缘由，主要是因为相关食品检验检测研究机构在对食品进行检测时往往采用一些比较落后的检测手段。
但是，如今食品中的添加剂愈发复杂与多样化，进而导致一些传统的检测方法和手段已经难以准确地检测并分析出食品的具体成分，故无法有效保障食品的安全性。
鉴于此，本文从三个方面展开阐述和说明。
1 采用电化学分析法对食品进行检测和分析电化学分析法是仪器分析法中较为重要的一种方法，常被用于食品检测。
但是，由于该方法对于检测环境的要求较高，因此，当检测环境不达标时，容易出现检测和分析上的误差。
基于电化学分析法的优缺点，相关食品检验检测研究机构在对食品进行检测时应灵活采用该方法对食品进行检测和分析。
例如，在对食品中的金属元素与混合元素进行检测分析时，可以借助电化学分析法来进行检测分析——对酱油、醋当中的砷含量进行检测分析时，应在保证检测环境未被污染的情况下使用该方法进行检测，从而准确测定酱油、醋中的砷含量。
2 采用光谱分析法对食品进行检测和分析光谱分析法是食品检测分析中常用的方法之一。
与电化学分析法不同，光谱分析法主要通过检测物质中的电磁波来对食品进行检测和分析。
该方法不仅检测结果更为精确，且检测范围更大。
鉴于此，相关食品检验检测研究机构在对食品进行检测时可以采用光谱分析法来对食品进行检测和分析。
比如，在对食品中的化合物进行检测时，可以借助光谱分析法进行分析：在对某些碳酸化合物饮料进行检测分析时，一方面，为了保证检测结果的准确性，需要严格按照国家食品安全检测标准来对食品进行检测;另一方面，需要定期分析和比对参照物以确保试验结果的准确性。
3 采用色谱分析法对食品进行检测和分析在所有仪器分析法中，色谱分析法是食品检验检测研究机构对食品进行检测时常用的一种方法，其不仅能够检测食品中的防腐剂、甜味剂等食品添加剂，还可以检测其中的一些营养元素。
检验检测38食品安全导刊2009年第3期梅特勒-托利多金属检测机确保肉类产品远离金属污染□梅特勒-托利多产品检测部门供稿肉类快速发展肉企面临的新挑战随着中国肉类消费市场的快速增长，国外肉类食品加工企业将进一步抢滩中国市场，而这必然会导致中国肉类市场的激烈竞争。
面对激烈竞争，企业必须明确几个方面的问题：①在品牌越来越多、竞争日益激烈的环境下，品牌形象和产品质量是胜出的关键；②肉类产品需求量的增加要求加工企业必须保持高效率的生产；③分布于各类超市、宾馆、酒楼的众多分销渠道必然导致客户群体的繁杂，必须努力提高质量管理力度，减少客户投诉事件的发生；④要具有对问题产品溯源的能力和准确界定责任承担的信心；⑤要非常清楚肉食加工行业总体利润较低，必须积极有效的降低生产、人力、管理等各面的成本。
对于面临的问题和挑战，国内的肉类加工企业必须采取相应的措施。
而要在激烈的竞争中胜出，以致更好的发展，必须采用有效的技术、设备提高产品质量、保障产品安全，有效降低各种成本。
目前不少企业开始关注生产中可能出现的金属异物、产品超重欠重等问题，不遗余力的引进先进的设备帮助实现对产品的质量控制，保持竞争力。
作为预防金属污染的重要设备，金属检测机的应用无疑会保障肉食品的安全，提高产品质量，增强顾客信心。
金属污染途径及关键控制点金属污然途径在肉类生产及加工中，金属杂质主要有三个面的来源：一是原料生肉中的金属标签、针头、金属丝等；二是操作工人的私人用品，如硬币、钥匙、发夹、图钉等；三是生产过程中机器设备产生的杂质，如生肉在切块、粉碎或搅拌过程中产生的机器损伤所造成的金属碎屑等。
金属污染的关键控制点根据实际生产情况确定的肉类生产及加工中的金属污染关键控制点是卫生检疫和深加工两个环节。
在卫生检疫环节，当给牲畜或者禽类注射疫苗或者进行消毒时，很可能会将注射针头遗漏在里面，造成金属污染；在深加工环节，如内脏分离和分割剔骨等由于需要使用刀具，金属杂质混入成品中的几率较大。
X光机操作规程一、日常操作顺序1、接通电源：X光机操作员将机器侧面的主电源开关置于ON档，将X光ON/OFF开关置于ON档，操作界面出现“ANRITSU”的图标，设备自检2分钟后出现基本界面。
2、操作员按下开始键，传送带开始运转，设备进入运行状态；按下停止键传送带停止运转。
3、受检品通过传送带，当被判定为合格品时，屏幕显示“OK”；当被判定为不合格时，屏幕会显示“NG”；屏幕统计数据显示所有受检品的总数、合格品数、NG数，但当受检品呈散乱状（无固定间隔）通过时，显示值会与实际不相符合。
4、新产品登记：新产品登记时，要进行基本设置与自动设置，本设备可登记100种产品的参数。
A、基本设置：1）变更产品编号：操作员在基本界面下按下产品键，然后从垂直滚动条中选择想设置的产品编号，按下变更产品按钮；操作中止则按下返回按钮，返回基本界面；2）操作员在基本界面上按下菜单键→产品登录→基本设置→输入品名（设置品名时，轻触文本框，出现键盘后输入文字）→选择判定形式（通常判定形式为“异物混入”）→显示（显示界面设置为“处理图像前”，基本形式设为“有效”）→运送（投光器使用设置为“使用”，工作状态设置为“包装”，输入传送带速度一般设置为“30～40m/分”）→登记→“小屋”键，以上各步结束，完成登录。
B、自动设置：操作员在基本界面上按下菜单键→产品登记→异物检测条件→设置异物检测算法（检测算法可在1至4间进行设置，一般设置为3，根据产品的形状也可设置为4。
若产品要求检出小的金属异物，也可使用1、2，但对骨头之类的异物检测灵敏度较低）→登记→返回→自动设置（显示准备中的界面，随即界面变换，3袋以上受检品逐一通过，显示X光管电压、电流。
由于受检品规格不一，需通过产品5-12次，检测次数与推荐检测水平会随受检品每次通过情况发生变化；当产品通过12次后，在显示界面上按下“是”，结束自动设置回到基本界面）。
5、灵敏度调节1）机器使用过程中，操作员每4小时一次对检测器的灵敏度进行调节（调节时要保证传递带上无任何物品；操作员每小时及产品更换时要附上测试片对机器的灵敏度进行校准）；2）操作员在基本界面上按下灵敏度修正键→下一步→显示正在进行灵敏度调节的界面→回到基本界面，灵敏度调节完成。
食品安全检测仪检测食品安全的方法及步骤食品安全检测仪可快速定量检测农副产品及其制品、日常食品及其制品、海产品及其制品中的违禁化学品（甲醛、硝酸盐、亚硝酸盐、二氧化硫等）和农药残留（有机磷类、氨基甲酸脂类），用户可根据自己的需求，随意组合，每个样品有程序控制分别独立工作，不会相互干扰。
食品安全检测仪预留其他项目检测程序和端口，可根据日后需求自主增加检测项目。
近年来，食品安全形势越来越严禁，世界各国都非常重视食品安全问题，先后值定理严格的监管措施，加强了监测力度，食品安全检测仪可检测的项目有：农药残留检测、三聚氰胺检测、激素及代谢产物检测、抗生素检测、霉菌毒素检测、动物疾病检测、禽病类检测等。
广泛应用于工商、农业和水产品等部门，亦可用于生产企业、农贸市场、超市、质量监督、卫生防疫等部门对食品安全的检测。
现在很多人都不太相信国内食品安全了，主要是因为这些年国内爆发了太多的食品安全事故了。
从“孔雀石绿”事件到苏丹红鸭蛋；从三鹿三聚氰胺毒奶到地沟油；瘦肉精、塑化剂、镉大米、毒豆芽、注水肉、上海福喜问题肉事件；假醋、假烟、假酒事件；过期月饼、过期药物事件。
2016年、2017年的网络平台违法销售餐饮事件、冒充知名品牌奶粉被查事件、亿元工业明胶用于制作食品进行销售事件。
还有滥施违禁农药、滥用药物和环境严重污染的有毒农产品事件。
食品安全问题涉及的品种之多，造假方式方法之广，违法违规手段之恶劣，让人惊心。
对于食品安全，一方面加强检测，避免不合格产品流向市场；另一方面则是加强立法，用法律规范企业行为。
食品安全检测仪使用原理：1.酶抑制率法在一定条件下，有机磷和氨基甲酸酯类农药对胆碱酯酶正常功能有抑制作用，其抑制率与农药的浓度呈正相关。
正常情况下，酶催化神经传导代谢产物（乙酰胆碱）水解，其水解产物与显色剂反应，产生黄色物质，在412nm处测定吸光度随时间的变化值，计算出抑制率，通过抑制率可以判断出样品中是否有高剂量的有机磷或氨基甲酸酯类农药的存在。
repaPetihWContents1 Why Submit Foods to X-ray Inspection?2 How Does an X-ray System Catch Contaminants?3 Factors Affecting the Sensitivity of X-ray Inspection2W h i t e P a p e rFood manufacturers are under increasing consumer and legislative pressure to provide safe food. One of the tools that helps to maintain food safety is x-ray inspection.This white paper looks at the use of x-ray inspection systems to eliminate physical contaminants on pumped food lines. It begins with a short introduction to x-ray inspection and why it’s used in the food-processing industry. It goes on to consider the factors that affect the sensitivity of x-ray inspection, the effectiveness of x-ray inspection at different points on the production line, and the ease with which the technology can be applied to production lines based on pumped product.After reviewing the factors that production line managers should take into account when considering installing an x-ray inspection system, the white paper suggests typical applications, and then looks at points to consider when using x-ray inspection for processed meat and poultry lines and for lines involving slurries, semi-solids, and fluids.Contamination Detection in Pumped Foods1. Why Submit Foods to X-ray Inspection?X-ray inspection systems keep foods safe by offering unsurpassed detection of physical contaminants. No other technology detects such a wide range ofcontaminants such as stone, metal, glass, bone, and high-density plastic and rubber.Incorporating x-ray inspection systems into a company-wide product-safety program helpsmanufacturers comply with national and international regulations - such as HACCP (Hazard Analysis Critical Control Point) - as well as standards set by retailers.Typical contaminants2. How Does an X-ray System Catch Contaminants?An x-ray system is essentially a scanning device. When a product passes through the x-ray system, the internal sensors capture a grey-scale image of the product. The software within the x-ray system analyzes the image and compares it to a predetermined acceptance standard.On the basis of the comparison, it accepts or rejects the image. In the case of a rejection, the software sends a signal to an automatic reject system/valve which removes the product from the production line.X-ray image of processed chickenWhite PaperMETTLER TOLEDO3Fig 1: X-ray image of a ready meal - lots of varities of greys make it more difficult to detect a contaminantFig 2: X-ray image of pumped caramel - it is easier to detect a contaminant in a homogenous product4. Establishing Critical Control Point for an X-ray System on a Production LineTo be fully effective, x-ray inspection should be part of a company-wide approach to product safety and part of a product inspection program. Implementing x-ray inspection into such a program helps foodmanufacturers to achieve compliance with standards such as HACCP .HACCP consists of seven steps known as principles.1. Conduct a hazard analysis2. Identify critical control point (CCP)3. Establish critical limits for each CCP4. Establish CCP monitoring requirements5. Establish corrective actions6. Establish record-keeping procedures7. Establish procedures to verify the system is workingas intended The second of those principles – identifying the critical control point (CCP) – helps to choose the best location to apply x-ray inspection on a production line. A CCP is a step or process that’s essential to product safety. It’s the point at which control must be applied to reduce the risk of contamination to acceptable levels.To find out more about selecting CCP, please read the white paper “How to select CCP for x-ray systems” (/usxray-ccp).White PaperMETTLER TOLEDO3. Factors Affecting the Sensitivity of X-ray InspectionThe ease with which food contaminants can be identified by x-ray inspection depends on various factors such as product density, product thickness, and product homogeneity.Product DensityProduct density determines the depth of grey in the grey-scale image. The denser the product, the darker the grey.To be detectable to x-ray inspection, a contaminant has to be denser than the product in which it’s embedded. That means it will absorb more x-rays than thesurrounding product, and show up on the grey-scale image as an area that’s darker than its surroundings. In other words, any contaminant with a density similar to, or less than, that of the product in which it’s embedded is incapable of being detected by x-ray inspection.Product ThicknessAs the product thickness in the path of the x-ray beam increases, so does its overall level of absorption. That makes detection more difficult. A contaminant in ashallow layer of product flowing through a pipe is easier to detect than a contaminant hidden inside a finished sealed pack. In general, the shallower the depth of product, the better the sensitivity of x-ray inspection.Product HomogeneityThe texture and consistency of a food product has an effect on x-ray sensitivity. A product with components of varying density, such as a ready meal, shows up in a greyscale image as a variety of greys (Fig 1). The more components there are, the wider the range of greys. Analyzing the image for contaminants is harder because the software has to pick out the tell-tale dark speck of a contaminant from an image containing numerous shades of grey. The more homogeneous the product, such as liquid caramel, the easier it is to spot contaminants (Fig 2).Many other factors can affect the sensitivity of an x-ray system. To find out more about the factors limiting the sensitivity of detection, please read “The X-ray Inspection Guide” (/usxray-guide).44.2 X-ray Inspection of Processed FoodWhen installed during or after the food processing or before the filling process, x-ray inspection of pumped products is ideal as they tend to be homogeneous - their texture and density are much more uniform. And since the product is already flowing through a pipe, it can easily be presented for inspection in shallow depths by narrowing the gauge or altering the cross-section of the pipe.X-ray systems for pumped products can be used at different stages on a production line depending on the identified CCPs.5. Applying X-ray Inspection to Pumped Food ProductsPumped products typically include meat and poultry as well as slurries, semi-solids and fluids at any stage prior to final packaging.Connecting x-ray inspection equipment to an existing piped production line isn’t complicated. Standard fittings are used to attach the pipe through which the pumped products passes to the manifold of the x-ray machine. The manifold typically tapers the round production-line pipe to a rectangular-shaped inspection window with an equivalent throughput volume. The rectangular section is where the x-ray beam scans the flowing product. The depth of product at this point is typically between 35mm to 50mm. When the software detects a contaminant, it diverts the product from the pipe via a reject diverter valve.A typical x-ray pipeline systemW h i t e P a p e rOnce the CCPs on a production line are identified, other factors such as practicality and cost-effectiveness need to be taken into account to select the ideal location for an x-ray system. There are occasions where it would be necessary to install more than just one x-ray system on the production line and that’s why there is no single solution that’s right for every production line.For this white paper, we will only focus on the inspection of pumped food products.4.1 X-ray Inspection at the Beginning of the Production LineDetection levels are typically better in the early stages of the production process where unprocessed pumped product can be presented in a shallower depth and with a more uniform texture. As the line progresses, thenature of contaminants can change too. Each processing step can introduce new contaminants, or break existing contaminants down into smaller, less detectable pieces.X-ray inspection of ground meatAt each stage of the production process, the value of the product increases. For that reason, food manufacturers find it more cost-effective to reject contaminated product before it’s been processed or sealed in its final packaging.Catching contaminants early is not just more efficient in reducing product waste and costs, it also helps prevent damage to processing equipment caused by big contaminants, which could in turn introduce more contaminants. Additionally, when installed early in the production process it can serve as a check on suppliers’ quality control.White PaperMETTLER TOLEDO6. Factors to Consider When Installing X-rayInspectionProduct passing through a pipe performs slightly differently to product travelling on a conveyor. To make the most of x-ray inspection, you need to take the following factors into account:Air BubblesAir bubbles in a pumped product are tiny voids – zones containing no product. Voids absorb fewer x-rays so they appear as lighter areas on grey-scale x-ray images. The contrast at the edges of these lighter areas can trigger the x-ray software into thinking that it detected a contaminant, causing false rejects. Since air bubbles reduce the depth of grey, they could lighten the color of any contaminants directly behind or in front. That makes the contaminants harder to detect.Air bubbles are common in pumped meat and poultry appications but are not difficult to eliminate with the right x-ray system design. A vacuum filler pump, for example, generates a constant, homogeneous flow with minimal air bubbles.Slurries and other viscous products do not normally contain air bubbles when pumped through a pipe. Speed VariationsA well-designed x-ray system will automatically adapt to changes in the flow rate of the customer product. It adjusts the scan speed and the associated reject timing in accordance with a speed signal from the production-line pump.Location on the Production LineAs mentioned previously, x-ray inspection can be applied anywhere on a production line containing pumped products. But the earlier you apply it, the better. The value of rejected product is lower, plus you may be able to recover the product and feed it back into the line after removal of the contaminants.A very common location is at the start of the production process when product value is low and the risk of contaminants from incoming raw product is at its highest. Using x-ray inspection at this stage also lets you monitor suppliers’ quality control.7. Typical ApplicationsA huge range of processed food products pass through pipelines. Typical applications could be:Meat andPoultrywhole muscle, minced meats forsausages, pies, pâtésBakery jams, syrups, cake mix and fillings Dairy butter, ice cream, yogurt, cottagecheeseFruit andVegetablespurées, mousses, juices,smoothies, chopped fruit andvegetablesFish andSeafoodfish spread, processed fish forready-mealsConfectionery melted chocolate, nougats, toffees Ready-Meals sauces, soups, pie fillingsWe can divide these food products into two broad classes: (1) meat and poultry, (2) slurries, semi-solids, and fluids. We’ll look at them separately.7.1 Meat and Poultry ApplicationsTypical pumped meat and poultry products include ground meat, sausage meat, and poultry trims such as breast fillets and thigh meat. Bone contaminants are by far the most common ones, although lead or steel shot (buck shot), needles, and teeth are also common. Depending on the pumped meat or poultry application, x-ray inspection can detect metal down to 0.8mm, and calcified bone and tooth down to 2mm. The maximum pipe diameter for meat applications is 75mm (3 inches) because narrower pipes make it easier to identify fragments of bone.White PaperMETTLER TOLEDO56W h i t e P a p e rSince chicken bones are less dense than red meat bones, they’re harder to detect. The density of chicken bone tends to be closer to that of the chicken meat in which it lies. On a grey-scale image, the difference between the grey of the meat and the grey of the bone is less obvious.Let’s look at some important points to consider when using x-ray inspection for pumped meat and poultry applications:• High volume throughput of up to 10 tons an hour • Contaminants will be removed before adding further value to the product through processing• Rejected product could be reworked and reused (depending on the application)•Reject portion sizes are larger than for aconveyorized x-ray system because the pipeline reject mechanism can’t isolate a single item such as a chicken breast fillet•Faster flows increase reject portion sizes – up to 2lb to 3lb of rejected product when running at 10 tons an hour through a 76mm (3-inch) pipe •High rejection rate due to frequency of bone contaminants in meat and poultry products – an acceptable reject level needs to be defined7.2 Slurries, Semi-solids and FluidsX-ray inspection is especially useful for products that cannot be sieved. These are products such as textured fruit purées and yogurts containing fruit chunks. Sieving removes physical contaminants by catching anything that’s too big to fit through the sieve mesh and is used mainly for liquid applications like milk. X-ray inspection of pumped products is a good alternative for catching physical contaminants where sieving can’t be used.The contaminants within slurries, semi-solids, and fluids are varied. Depending on the application, x-rayinspection can detect metal down to 0.8mm, glass and stone down to 2mm, and dense plastic down to 4mm. The maximum pipe diameter for these more fluid applications is 100mm (4 inches).Contaminated slurries, semi-solids, and fluids are typically rejected from the pipe through a diverter ball valve. The ball valve automatically removescontaminated product without creating a back pressure in the system.The sanitary design of an x-ray system inspecting slurries, semi-solids, and fluids is very important. For more efficient cleaning, aseptic x-ray inspection systems are available. An aseptic design incorporates steam-cleaning ports for destruction of pathogenic bacteria growth. For dairy applications, there are x-ray inspection systems that are certified to AMI and 3-A Sanitary Standards.Let’s look at some important points to consider when using x-ray inspection for slurries, semi-solids and fluids:•High volume throughput of up to 20 tons an hour – larger than for meat and poultry because pipeline diameters are typically greater and fluids can travel faster through pipes• Contaminants will be removed before adding further value to the product through processing• Rejected product can be reworked and reused (depending on the application)•Faster flows increase reject portion sizes – up to 5kg or more of product when running at 20 tons an hour through a 100mm (4-inch) pipeWhite PaperMETTLER TOLEDO8. ConclusionFor many years, x-ray inspection has proven itseffectiveness at eliminating contaminants fromprocessed and packaged food products. Theeffectiveness of x-ray inspection systems dependson the product density, thickness and homogeneityof the inspected product.Since pumped products tend to be more homogeneous,it’s easy to adjust their depth by altering the size orshape of the pipe through which they flow. That makespumped products an ideal application for x-rayinspection, offering food manufacturers excellentlevels of contaminant detection.Pumped products on a food processing line tendto occur early in the production process before amanufacturer has added further value to the productthrough processing and packaging. Since product valueis lower at this point, this location is very common forx-ray inspection system for removing contaminants.Early removal of contaminants has two otheradvantages: it protects valuable processing equipmentfrom damage further downstream, and it serves asa check on suppliers’ quality control.Installing x-ray inspection equipment on a pumpedproduction line is a simple process. A pressure vacuumpump will eliminate air bubbles especially in meat andpoultry applications. A well-designed x-ray inspectionsystem can also automatically change the scanningspeed and the reject timings to match the customer’sflow rate.X-ray inspection is a versatile technology that’s suitablefor the inspection of a wide range of pumped foodproducts at CCPs on a food processing line. It helpsmaintain product safety and brand reputation, andcan protect valuable equipment from damage.7White PaperMETTLER TOLEDOFor more informationMettler Toledo Safeline 6005 Benjamin Road Tampa FL 33634 USATel. 813-889-9500Toll Free 800-447-4439Fax. 813-881-0840Email:*********************Subject to technical changes©05/2011 Mettler-Toledo Safeline Printed in the US/safelineusOn-Demand X-ray Webinars 24/7Our on-demand webinars give you the opportunity to learn more about x-ray inspection - at your own convenience!To view all our on-demand webinars please visit:/pi-ondemandFurther Information about X-ray InspectionFREE Technical Guide Make an informed decisionMETTLER TOLEDO has published an authoritative product inspection guide for x-ray inspection systems.The 73 page guide enables you to select the right x-ray inspection system for your production line. It supports you to install an all-encompassing product inspection program and to achieve compliance with standards, regulations and legislation.Register today for your FREE copy:/pius-guidesFREE White PapersHow Safe is X-ray Inspection of Food?Some of the most popular misconceptions about x-ray inspection of food are tackled in this White Paper. It is an indispensable white paper for food manufacturers who consider x-ray inspection to comply with food-safety regulations and legislations.Register today for your Free copy: /xrayus-safetyX-ray Inspection: More Than Just Contamination DetectionX-ray inspection can detect numerous quality shortfalls that lie hidden within product packaging or deep within the product itself. This white paper explains that x-ray inspection is no longer just a technique for catching contaminants; its become a wide-ranging tool for defending brand values and keeping customers happy.Register today for your Free copy:/xrayus-integrity。
含油食品酸价检测不确定度评定张学英（湘西州食品药品检验所，湖南吉首416000）摘要酸价是反映食品中油脂酸败程度的重要指标，也是食用油或含油食品中必检项目之一。
酸价检测不确定度评定可以更科学地评价酸价检测的准确性、科学性和公平性。
本文采用冷溶剂指示剂滴定法与冷溶剂自动电位滴定法检测酸价，建立数学模型，分析不确定度来源，评定各不确定度分量、合成不确定度及扩展不确定度。
结果表明，自动电位滴定法检测某含油食品酸价结果为6.4mg/g，扩展不确定度为0.2mg/g，K=2，显著性不确定度分量为NaOH标准滴定液浓度；指示剂滴定法酸价为6.3mg/g，扩展不确定度为0.3mg/g，K=2，显著性不确定度为NaOH标准滴定液浓度不确定度最大、A类不确定度次之、滴定体积不确定度再次之，且三者显著性相近，扩展不确定度大于电位滴定法。
通过不确定度评定和显著性分析，可以有针对性地找到降低或控制检测误差的方法，提高检测结果准确性。
关键词含油食品；酸价；不确定度评定；冷溶剂指示剂滴定法；冷溶剂自动电位滴定法中图分类号TS207.3文献标识码A文章编号1007-5739（2024）04-0130-06DOI：10.3969/j.issn.1007-5739.2024.04.033开放科学（资源服务）标识码（OSID）：Assessment of Uncertainty in Acid Value Detection of Oil-containing FoodZHANG Xueying(Xiangxi Prefecture Food and Drug Inspection Institute,Jishou Hunan416000) Abstract Acid value is an important index reflecting the rancidity degree of oil in food,it is also one of the items that must be tested in edible oil or oil-containing food.Assessment of uncertainty in acid value detection can scientifi-cally assess the accuracy,scientificity,and fairness of acid value detection.This paper used the cold solvent indicator titration and the cold solvent automatic potentiometric titration to detect acid value,established a mathematical model, analyzed the sources of uncertainty,then assessed each uncertainty component,combined uncertainty,and extended uncertainty.The results showed that,through the automatic potentiometric titration,the acid value detection of a certain oil-containing food indicated C=6.4mg/g,U=0.2mg/g,K=2,and the significant uncertainty component was the concen-tration of NaOH standard titration solution.The acid value detected by the indicator titration indicated C=6.3mg/g,U= 0.3mg/g,K=2.The concentration of NaOH standard titration solution had the highest significant uncertainty,followed by class A uncertainty,and the titration volume uncertainty,the three had the similar significance,and the extended uncertainty of indicator titration method was greater than that of the potentiometric method.Assessment of uncertainty and significance analysis,can find targeted methods to reduce or control detection errors and improve the accuracy of detection results.Keywords oil-containing food;acid value;uncertainty assessment;cold solvent indicator titration method;cold solvent automatic potentiometric titration method食用油脂及含油食品是人民日常生活必不可少的物质，油脂是中国居民膳食指南重要组成部分，是人体所需三大宏量营养素之一[1]。
安检x光机原理
安检X光机是一种常用的安全检测设备，它通过发送X射线束来检测被检物体的内部结构和组成。
安检X光机的原理主要基于X射线的透射性质。
X射线是一种高能电磁辐射，具有很强的穿透能力，可以穿透人体内部物质，并被不同组织和物质以不同的方式吸收，形成X射线像。
安检X光机通过产生高能的X射线束，并将其照射到被检物体上。
被检物体吸收或散射部分射线，并形成一个衰减的X射线束。
这个衰减的X射线束经过探测器的测量和分析，可以还原出被检物体的内部结构和组成。
在安检X光机中，探测器被设计成能够测量和记录通过其上的X射线的强度。
当未被物体阻挡的X射线通过探测器时，探测器会记录到一个基准值。
然后，当被检物体放置在X射线束中时，通过探测器记录到的X射线强度会减少。
根据这种强度的减小程度，可以得出被检物体的密度、组织等信息。
安检X光机在安全检测中被广泛应用，可以用于检测行李、货物、人体等。
它能够快速、准确地检测出携带危险物品或禁止物品的情况，对于保障公共安全和防止恐怖袭击起到了重要作用。
但同时，也要注意合理使用X射线设备，减少对人体的辐射危害。
如何用异物检测技术避免食品安全问题作者：DanielaVerhaeg来源：《食品安全导刊》2016年第02期现如今，全球市场依旧处于日益激烈的竞争中，维持食品制造商与零售商之间稳固关系的重要性前所未有。
随着消费者持续密切关注食品安全问题，零售商需要制造商始终提供高质量的食品。
在食品到达超市货架或销售之前，制造商必须检出并剔除任何潜在的污染物，如玻璃、金属或矿石等。
为了维护自身品牌在消费者心中的声誉，大型高级零售商甚至引入其自己制定的食品安全准则，并要求制造商必须按照此准则来提供所需要的食品。
如果食品生产商为零售商提供了劣质产品，他们之间的合作极有可能会被取消，零售商会接着与其他准备接手的制造商展开下一步合作。
因此，对于制造商而言，找到可靠的方式来确保食品安全、提高食品质量，以及最大限度地减少食品遭受外物污染的风险至关重要。
与此同时，食品制造商也正在见证零售商对玻璃包装日益增长的需求。
这是因为零售商开始强调食品的可持续性战略，旨在迎合消费者日益重视的环保需求。
由于玻璃是100%可回收的材料，它更能让消费者在购买食品前清楚地了解食品的状态和外观，而且其透明特性也能赋予超市货架上的食品一种让人无法抗拒的吸引力。
据相关数据分析得出，全球玻璃市场预计将在2014～2020年之间增长3.6%。
除此以外，根据更多调查显示，当食品采用玻璃包装时，消费者对于食品污染的顾虑会有所减少。
玻璃包装所带来的挑战玻璃包装为制造商的食品检测带来了特殊的问题，鉴于玻璃具有的高密度特性，检测玻璃包装材料中是否存在污染物将充满难度与挑战。
在检测液体中是否存在高密度异物时，如检测酱油中是否存在玻璃或金属碎屑时，此类外物有可能沉入包装底部；而当包装材料采用玻璃时，需检测的部位恰好正是玻璃厚度最大的地方。
此外，某些容器底部的凸起圆顶会让制造商更加难以检测污染物。
如果污染物密度比较小，则会融入食品中，甚至会停留在玻璃包装的顶部。
尤其是在检测碎玻璃污染物时相当棘手，因为污染物与包装材料的密度相同。
X光机的操作流程1.先查看面板调节旋钮，电源调节旋钮是否都在最低位置。
2.将电源开关置于“I”，机器通电。
3.电源调节，旋钮到电压表刻度指于220V处。
4.千伏调节，旋钮到所需要的千伏值。
5.时间调节，选择到所需要的时间。
6.选择适当毫安值，30MA或50MA.7.将放有X线胶片的暗盒放置于抽屉中，焦距为90CM。
8.调节限速器，将限速器的示野调大，并使其十字中心线与暗盒的中心线相重合。
在暗盒上放上铅字以变方向。
9.按下手开关，听到蜂鸣器有“嘟”叫声，并有毫安表同时指.示，表示曝光顺利。
10.遥控曝光，曝光时，一旦机器接到发射信号，即计时曝光。
11.摄影完毕之后，将千伏时间还原，然后关掉电源开关。
12.洗片，在暗房中，把红灯打开，在取出胶片，夹于洗片架上，在放于显影箱中，等待大概1分钟左右取出，在红灯下观察是否显起，如果没有显起在放入显影箱内，直到显起为止，13.从显影箱内取出胶片后用清水清洗后在放入定影箱内，大概15分钟后取出，然后晾干。
摄影技术X线摄影时，除必须具有X线诊断机外，还需一些不可缺少的器材，如X线胶片、片夹、增感屏、遮线管、滤线器、铅号码、摄影架、测厚尺等。
X线摄影条件的确定，应根据投照部位、厚度、千伏值（KV）、毫安秒（MAS）及焦片距离（D）等因素。
犬X线摄影前，应禁食12小时，投照部位的厚度以8~9cm计算，投照距离（D）为90cm，管电压为65KVP，x线量可选用1.7、2.5、5.0mAS，或用相近的量摸索最佳效果。
投照条件在以上情况下，变化原则如下。
（1）管电压在80kVp以下时，投照部位的厚度每增减1cm，相应增减2kVp。
（2）管电压在80kVp以上时，投照部位的厚度每增减1cm，相应增减3kVp。
（3）投照部位厚度在10cm以上时，管电流或曝光时间应增加3倍。
（4）X光机的性能达不到所要求的管电压时，可按表7进行。
减低管电压，同时要增加1倍的X线量（MAS）。
（5）投照胸部或幼犬时，mAS应减少一半。
