china “gutter oil” unsolved qualitative detection...

中国特色“地沟油”及其检测定性之无解终局China “Gutter oil” unsolved qualitative detection methods

曹文明博士/研究员Wenming Cao, PhD & Professor

上海市粮食科学研究所Shanghai Grain Science Research Institute

Nov. 19th, 2014 • Shanghai1

上海市粮食科学研究所SHANGHAI GRAIN SCIENCE RESEARCH INSTITUTE

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提纲 Outline

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1.中国特色“地沟油”China version “gutter oil”

2.“地沟油”的物化属性分析Physical and chemical analysis on “gutter oil”

3.“地沟油”鉴别方法的探索Research on detection methods for “gutter oil”

4.“地沟油”筛查应用展望Perspectives of “gutter oil” screening techniques

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震惊世界：2010年中国媒体披露“地沟油”内幕In 2010, a report shocked the world that 3,000,000 tons of

“gutter oil” consumed by Chinese every year.



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废弃动物内脏油脂Waste animal fat from abattoir

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千百年来“地沟油”仅指阴沟油China version “gutter oil” originated from the shocking report.

The traditional concept was only “sewage oil”.

Sewage oil

Gutter oil

Kitchen waste oil Spent frying oil


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“地沟油”司法解释:(餐厨垃圾+废油+废肉）为原料；非科学定义，废弃物料不能定标准，指代不明。

The judicial interpretation is the oil made from such raw materials as ①②③.

This isn’t a scientific definition because the waste is unable to be standardized.

①餐厨垃圾Kitchen waste

②废弃油脂Recycle waste oil

③肉及肉制品加工废弃物Abattoir and meat processing waste

2010年前 “地沟油”从未指代废弃油脂Before 2010, “gutter oil” never referred to all the waste oil


“Gutter oil”

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中国“地沟油”现状：远低于300万吨，主要老油、无阴沟油、泔水油少

Actual status: The amount of “gutter oil” is much less than

3,000,000 tons every year.


Spent frying oil

(Majority)

Sewage oil

(None)

Kitchen waste oil

(Minority)

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老油使用具全球普遍性：各国煎炸油废弃标准不同If it were classified as “gutter oil”, reusing spent frying oil apparently

constitutes a global issue. The regulations on end of frying oil differ

from countries.


“地沟油”无标样：油脂的无限组合，无固定化学组成“Gutter oil” has no reference standard, no fixed chemical

composition. It’s infinite kinds of combination of oil, maybe

pure or mixed.

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2.“地沟油”的物化属性Physical and chemical analysis on “gutter oil”

地沟油样品：单一或混合油“Gutter oil ”samples :

pure or mixed oil

油脂主要成分：三酰甘油混合物Major components in oil&fat:

mixed triacylglycerols

精炼可修复理化指标: “地沟油”提炼手段多样Such physical and chemical indicators as PV,AV and color

may be “recovered” through various refining methods.

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PV improved by re-refining

精炼过程中地沟油过氧化值的变化

0

5

10

15

20

25

粗毛油脱色脱臭

mmol/kg

11#

37#

93#

104#

132#

13#

14#

21#

32#

40#

46#

81#

92#

27#

28#

30#

31#

Various possible recycle paths


聚合物（TGP） : 油脂氧化抹不掉的痕迹Triglyceride polymers (TGP): TGP is an indelible imprint of oil

oxidation. TGP content is low in fresh edible oil.

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储藏、使用、废弃、精炼过程中TGP含量持续递增TGP increases continuously in storage, use, discard and refining

• 新鲜油 Fresh edible oil 货架期聚合Polymerization

within shelflife

使用时聚合Polymerization

during use废弃时聚合Polymerization

after discard

精炼时聚合Polymerization

during refining

聚合物（TGP）: 精炼过程持续递增During refining ,TGP contents of the crude oil, degummed oil,

bleached oil, deodorized oil increase continuously.

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聚合物（TGP）: 储藏中持续递增TGP contents also increase during storage. In the early stage they

maintain flat, then rise rapidly.


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B:聚合物 TGP ; C:单体 Triacylglycerol

1：脱臭油 deodorized gutter oil

2：脱色油 bleached gutter oil

3：毛油 crude gutter oil

聚合物（TGP）:地沟油TGP不能通过再次精炼修复TGP in “gutter oil” is unable to be erased by re-refining.

Its content increases from line 3 to line 1 during re-refining.


缺失共性特征: 外源性指标的偶存性“Gutter oil” has no common specific indicator. All exogenous

indicators such as animal genes, capsaicin and detergents exist in oil

accidentally.

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动物基因 Animal DNA

辣椒素 Capsaicin

洗涤剂 Detergent

氯化钠 Sodium chloride

……

重金属 Heavy metal

真菌毒素 Mycotoxin

多环芳烃 PAHs

胆固醇 Cholesterol

……

外源污染物种类、污染的途径具随机性Randomness of routes and sources of exogenous contaminants


“地沟油”阈值难以确定：内源性指标的连续递变性It’s difficult to set the threshold value of the indicators between edible

oil and “gutter oil”, because endogenous products change continuously.

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油脂劣变途径Paths of oil deterioration

内源性产物不间断递变Endogenous products increase continuously

氧化

水解

热质变

Time

Co

nte

nt


“地沟油”特异性指标：理论上不存在There is no specific indicator for “gutter oil” theoretically. Both false

negative of exogenous indicators and false positive of endogenous

indicators are inevitable.

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外源性物质偶存，内源性物质共存Random exogenous and coexistent endogenous substances

内源性

食用油Edible oil

地沟油“Gutter oil”

En

dog

eno

us

外源性Exogenous


“地沟油”特征峰或特征谱图：理论上不可能In theory, it’s impossible to identify “gutter oil” by specific peak or

spectrum because the accurate mechanism of peak formation is

unknown.

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假定的“特征”低场核磁峰Assumed specific peak of low frequency NMR

○假定的“特征”拉曼光谱峰

Assumed specific peak of Raman

地沟油快速检测


“地沟油”特征峰或特征谱图：不成立的经典案列This is a typical invalid case. The left figure shows the specific peaks in

“gutter oil” of different intensity. The middle figure has no such specific

peak in edible oil. Both appear exceptional cases as in right figure.

Exceptional cases 18


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特征峰例外案列

地沟油Gutter oil

食用油Edible oil

假定的地沟油核磁特征峰Assumed specific NMR peaks

食用油无特征峰No specific peak in edible oil

例外的油Exceptional oil


准确率：样本依赖性，非方法准确率The accuracy of all methods depends on oil types on the samples.

The detection accuracy varies from 75% to 100% by the same method.

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75% 100%

85% 90%

“地沟油”盲样（来自国家食品安全风险评估中心）“Gutter oil” blind samples （from CFSA）


排除法不可行：食用油与“地沟油” 不是非此即彼Exclusion method was inapplicable because a rigid

dichotomy between edible oil and “gutter oil” is unfeasible.

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双非油的存在使得排除法不成立Exclusion method is invalid when there are 3 oil types


双非油 Oil of neither

1.非食用油（桐油„）

Inedible oil (tung oil、castor oil….)

2.过期废油

Expired edible oil

3.指标不合格废油脂

Off quality oils and fats

4.„„

地沟油“Gutter oil”

食用油Edible oil

双非油Oil of neither

双盲法:不适于评价“地沟油”检测方法Double-blind evaluation is not applicable for “gutter oil” detection methods.

盲样界定存在争议；不能忽视第三类“双非油”的存在Identification of blind samples is always controversial . The existence of “oil

of neither ” should not be ignored.

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三种结果：阳性、阴性、未知Three kinds of possibilities: positive, negative, unknown

+地沟油

“Gutter oil”

-

食用油Edible oil

?双非油

Oil of neither

互补的定向与非定向方法:提高准确率Complementary system with targeted and non-targeted

detection helps to increase accuracy.

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非定向方法Non-targeted detection

· 不需要掺假物信息 .

No need information on specific

possible adulterants

· 可检测任何掺假物

Applicable to any adulterants

定向方法Targeted detection

· 必须有掺假物信息

Prerequisite for information

on specific adulterants

· 不能测未知的新掺假物

Unable to detect new unknown

adulterants

定向与非定向结合的检测方法更优Best to combine both the approaches


筛查方法：具有必然性Screening technique is the only detection method.缺失特异性标记物，不能100%准确；假阳性与假阴性都不可避免。

It’s impossible to have 100% accuracy because of absence of specific

indicator or marker. Both false positive and false negative are inevitable.

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假阳性---概念模糊，外源标记物经原料、容器、物流、人为等偶然迁入False positive is inevitable because of vague concept and accidentally

contaminated exogenous factors from raw materials, containers, logistics

and artificial addition.


查证是唯一鉴定方法: 十大地沟油案件无一靠检测侦破Verification on documentary evidence was the only sure method.None of 10 major “gutter oil” cases in China was confirmed by detection

method.

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* 查获地沟油6万吨Seize 60,000 tons of “gutter oil”

* 涉及28个省60个窝点Involving 28 provinces and 60 sites

* 犯罪嫌疑人700余名More than 700 suspects

* 中国十大“地沟油”案例10 major “gutter oil” cases in China


系列措施1：严打地沟油犯罪Series of measures 1: cracking down on “gutter oil” crime.

Only 60,000 tons of “gutter oil” was found , much less than expectation.

当前 “地沟油”市场:秩序可控，措施有效A series of effective measures lead the current “gutter oil” market

orderly and under control.

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系列措施2：收运处置许可证制度Series of measures 2: licensing the collection and disposal of

waste oil

2 disposal and about 20 collection companies are licensed in SH.

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系列措施3：推广油水分离器Series of measures 3: promoting the use of oil trap in restaurants

Oil trap

Oil trap

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系列措施4：取消散装油销售Series of measures 4: to ban bulk oil retail

上海、济南、长沙、北京、海南、青岛、西安、乌鲁木齐、北海等城市2012年前已禁止散装油销售„„

Before 2012, bulk oil retail was

banned in Shanghai, Jinan,

Changsha, Beijing , Hainan,

Qingdao, Xi’an, Urumqi, Beihai etc.


筛查与监察:相得益彰Screening and supervision are mutual supportive

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重点督查Critical points supervision

有效筛查Effective detection

* 圈定重点：严打代价高，不能成为常态* 威慑罪犯：无检测方法则犯罪更猖獗Screening can not only narrow down the supervision scope but also deter

criminals. Routine inspection is too costly, but no detection techniques may

result in more cases.



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1）老油指标：TGP

TGP is an excellent indicator of spent frying oil. It represents the

degree of oil deterioration.


TGP increases during refining and heating.

筛查技术发展方向之一: 特定类别油的特异性指标One of screening technique directions is the indicator for specific oil type.

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2）泔水油指标：三氯丙二醇酯、辣椒素、二氢辣椒素3 excellent specific indicators for kitchen waste oil：3-MCPD,

capsaicin and dihydrocasaicin



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3）动物油指标：奇数与支链脂肪酸Odd and branch chain fatty acids are better specific indicators for animal

fats.The red data (animal) differ from the green ones (vegetable) significantly.

Category FATS C-17 ISO-17 C-15 ISO-15

Animal fats

鸡油 864 18 501 11

猪油 2484 86 380 10

黄油 6869 3399 6268 2249

牛油 19259 6482 12787 4885

羊油 26817 5379 11601 2120

Vegetable oils

麻油 470 0.27 14 0.15

葵花油 584 0.14 142 0.13

橄榄油 607 0.12 40 0.08

玉米油 735 1.49 83 0.23

豆油 1196 0.34 165 0.13



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核磁共振谱 NMR离子迁移谱 IMS


筛查技术发展方向之二: 非定向识别谱图法，基于样品差异总量Another important screening technique direction is non-targeted

spectrometry based on the total samples differences.

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基于TGP的筛查技术：TGP表征油脂氧化聚合程度Screening technique based on TGP: TGP represents the degree of oil

polymerization. Before detecting TGP by HPSEC ,the polar components

should be isolated first.

HPSEC测定油脂TGP

Detecting oil TGP by HPSEC


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基于TGP的筛查技术：量化数据与峰形特征Based on TGP screening technique, each oil type has a group of

quantized data and featured peak.

典型的油脂HPSEC图及对应数据Typical oil HPSEC spectrum and corresponding data


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基于TGP的筛查技术：合格食用油TGP值普遍低Low TGP content in good quality edible oil

中外食用油脂中的TGP含量TGP contents of edible oil are usually below 2%

Other countries edible oil Domestic edible oil


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基于TGP的筛查技术：地沟油TGP值区间显著偏离Detection from over 100 random “gutter oil” samples showed their TGP

contents deviate significantly from those of edible oil, average 7 times higher .


TG

P C

on

ten

t %

Edible oil Gutter oil

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基于TGP 筛查判定的地沟油与棕榈油“Gutter oil” and palm oil screening based on TGP


Reused palm oil“Gutter oil”

基于TGP的筛查技术：TGP筛查“地沟油”典型案例1-2Blind samples (1 and 2) are from CFSA. “Gutter oil” was confirmed based

on TGP screening technique. Whether the reused palm oil is “gutter oil” or

not remains controversial.

1. 2.

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基于TGP的筛查技术：TGP筛查“地沟油”典型案例3-4Blind samples (3 and 4) are from CFSA. Corn oil and soybean oil were

confirmed by TGP screening technique.

基于TGP 筛查判定的玉米油与豆油Corn oil and soybean oil screening based on TGP


Corn oil Soybean oil

3. 4.

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IMS筛查技术：大气压条件下，气化的待检物电离后在电场中迁移

的离子时间特征分辨谱，具指纹特征Another representative screening technique is ion mobility spectrometry

method (IMS).


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IMS筛查技术：“地沟油”与食用油共27583组数据IMS is a kind of recognition technique. The first step is to build the data

bank. 27,583 groups of IMS data (including “gutter oil” and edible oil) have

been built.


Samples

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IMS筛查技术：“地沟油”分类谱图，盲样识别率高于90%These are IMS spectra of three main “gutter oil” types. With the software ,

rate of success in identification of blind samples is over 90%.

阴沟油Sewage oil

老油Spent frying oil

泔水油Kitchen waste oil


动物废油Waste animal fat

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花生油

茶籽油Camellia seed oil

花生油Peanut oil

橄榄油Olive oil

菜籽油Rapeseed oil

IMS筛查技术：食用油谱图，盲样识别率高于96%These are IMS spectra of olive oil, rapeseed oils, peanut oil, and camellia

seed oil. Rate of success in identification of blind samples is over 96%.


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IMS筛查技术：食用油谱图，盲样识别率高于96%These are IMS spectra of the sunflower seed oil, soybean oil, rice bran oil

and palm oil . Rate of success in identification of blind samples is over 96%.

米糠油棕榈油棕榈油米糠油棕榈油

葵花籽油Sunflower seed oil

米糠油Rice bran oil

大豆油Soybean oil

棕榈油Palm oil


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本所主持完成的“地沟油” 研发项目“Gutter oil” R&D projects led by SH grain scientific institute

1. 2010年上海市应用技术研究专项《餐厨废油脂…的研究》编号2010-115

Major project of Shanghai applied technology development in 2010

2. 2011年上海市应用技术研究专项《 …内源性地沟油特征指标的研究》编号 2011-118

Major project of Shanghai applied technology development in 2011

3. 2011年上海市科委科研计划《…地沟油特异性指标的研究》编号11231200100

Science research program of Science and Technology Commission of

Shanghai Municipality in 2011

4. 2011年上海市科委科研计划《…快速检测地沟油专用仪器的研制》编号11142200400

Science research program of Science and Technology Commission of

Shanghai Municipality in 2011

5. 中国矽感科技重大研究开发专项《IMS检测再生油…开发》20131220146

Major R&D project of China Syscantech Group

Total sum of our research projects funded by government and enterprises is

over 10,000,000 RMB.

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关于“地沟油”的若干重要结论

Conclusions

1. “地沟油”非科学概念，指代不明；

“Gutter oil” is not a scientific term, therefore cannot be defined.

2. 理论上不存在“地沟油”特异性指标，定性定量都不可能；

Specific indicator of “gutter oil” theoretically does not exist,

therefore impossible to establish qualitative and quantitative

detection method.

3.任何检测技术只能用于筛查，查证是唯一的鉴定方法；

Any screening technique has to be verified and supported by

other collaborative evidence.

4. 地沟油检测方法的准确率与灵敏度具样本依赖性，不可能检测掺伪量；

The accuracy and sensitivity depend on samples, unable to

quantify the amount of the adulteration.

5. TGP指标与IMS筛查技术具有应用前景。

TGP and IMS analytical techniques are applicable.

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“地沟油”项目研发核心团队Key workers in the team of “gutter oil” projects

薛斌陈凤香陈卫栋王文高袁超曹洁朱天仪包杰印瑜洁李以隽陈纯丁丹华王俊杰曹文明

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Tel: 86 21 62051351

Mobile: 86 18017491779

E-mail: [email protected]

china “gutter oil” unsolved qualitative detection...

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