310 likes | 777 Views
Testing services for nutrition labelling provided by local laboratories by Dominic Lam Hong Kong Association for Testing, Inspection and Certification Limited 香港測檢認證協會有限公司 Background
E N D
Testing services for nutrition labelling provided by local laboratories by Dominic Lam Hong Kong Association for Testing, Inspection and Certification Limited 香港測檢認證協會有限公司
Background Hong Kong Association for Testing, Inspection and Certification Limited is an independent and non-profit making organization, founded by a group of testing laboratories, inspection companies and certification bodies
Background (continuous) One of our major objectives is to enhance the standard and quality of testing, calibration, inspection and certification for the furtherance of international trade and consumer satisfaction.
Presently there are about 164 laboratories with HOKLAS accreditation. About 7 of them are commercial laboratories accredited for nutrition labelling testing services. (information provided by CFS) Centre for Food Safety (CFS) recommends the selection of laboratories that are accredited to ISO/17025 standard under HOKLAS. However, ISO/17025 accredited laboratories from other countries can also be used.
General steps of food analysis sample homogenisation extraction concentration detection reporting
Method used (使用方法) • Suitable methods suggested as below: • Most recent edition of AOAC international (美國公職分析化學家協會) • Manuals of Food Quality Control of Food and Agricultrue Organization of United Nation. (聯合國粮食及農業組織) • ISO or BS EN(國際標準組織 或 歐盟 • 標準) • Other national standard methods
Protein 蛋白質 (AOAC 928.08 or AOAC 992.15) • Based on nitrogen content obtained by Kjeldahl method or combustion method. • Apply nitrogen conversion factor to give the food protein content. • For general food, multiply nitrogen content by a factor of 6.25; but for milk it is 6.38 (milk), soybean 5.70 etc.
Total fat 脂肪總量 (AOAC 992.06) • Sum of triglycerides (三酸甘油脂), phospholipids, wax ester, sterols and minor amount of non-fatty material. • Acid hydrolysis followed by extraction and then by gravimetric method to measure the total fat content. • Not to use the amount of triglycerides to measure the total fat content.
Saturated fatty acid 飽和脂肪酸(AOAC 996.06) • Refers to the sum of fatty acids that without double bonds. • The fatty acids are
Saturated fatty acid 飽和脂肪酸(AOAC 996.06) • Determine the fatty acids by use of Gas Chromatographic method (氣相色譜法). 氣相層析儀/火焰離子化分析法
Trans fatty acid 反式脂肪酸(AOAC 996.06) • It is the sum of all unsaturated fatty acids (不飽和脂肪酸) which contains at least one nonconjugated and trans double bond. saturated fatty acid cis unsaturated fatty acid trans unsaturated fatty acid
Trans fatty acid 反式脂肪酸(AOAC 996.06) • The trans fats are referred as • Determine the fatty acids by use of Gas Chromatographic method (氣相色譜法).
Sodium 鈉(AOAC 969.23 or AOAC 985.35) • Salted food contains large amount of Sodium as salt is sodium chloride. • Sample is acid digested and followed by instrument ICP-OES measurement.
Sugar 糖 (AOAC 980.13) • Means all monosaccharides (單糖) and disaccharides (雙糖) present in food. • Monosaccharides: Fructose, Galactose, Glucose • Disaccharides: Lactose, Maltose, Sucrose
Sugar 糖 (AOAC 980.13) • Sample is extracted in solvent followed by HPLC-RI analysis. • Traditionally method of reducing sugar is used, but it is not applicable to food with high sucrose content (because sucrose is not a reducing sugar). The sugar content will be underestimated.
Dietary fiber 膳食纖維總量 (AOAC 985.29) • Only AOAC methods can be used since dietary fiber is method dependent. • Sample is firstly defatted, protein and carbohydrates will be hydrolysed by enzyme, finally dietary fiber is measured by gravimetric method (重量法).
Alcohol (ethanol) 酒精 • Measurement of alcohol is necessary for food significantly contains alcohol. • Examples are alcoholic beverages, desserts with alcohol etc. • It can be accurately measured by Gas chromatographic method. Chocolate with wine inside
Organic acids 有機酸 (AOAC 986.13) • Codex (食品法典委員會) does not provide a definition. • Some prepackaged foods contain significant amount of organic acids. • Eg fruit juice (citric acid), milk (lactic acid). • Liquid chromatographic method (液相色譜法)is preferred.
Water content 水份 (ISO1442:1997) • Weigh the sample after it is dried at 105oC. • Total Ash 灰分總量 (ISO 936:1998) • Weigh the sample after it is incinerated at 550oC. Furnace
Carbohydrates 碳水化合物總量 • It is by calculation not by tests. • I. Total carbohydrates = • available carbohydrates + dietary fiber • II. Available carbohydrates = • 100 - [protein(g) + fat(g) + water(g) + ash(g) + alcohol(g) + dietary fiber(g)]/100g of food
Energy 能量 • It is by calculation not by tests. • Energy value kcal/100g = available carbohydrates x 4 + total fat x 9 + protein x 4 + alcohol x 7 + organic acid x 3 • Energy value KJ/100g = Energy value kcal/100g x 4.2 (1kJ = 4.2kcal)
Case studies 個案分析 (食物安全中心提供) • 1. If some products are packed in liquid, should the water be analysed? • Case by case • If the solid part is usually consumed with the liquid, the whole package should be analysed.
Case studies 個案分析 (食物安全中心提供) • 2. For health foods packed in the form of “capsule”, should the capsule be analysed together? • As the capusle is usually consumed together, the content of the whole capsule should be analysed. Unless it is clearly specified that the content in the capsule should be removed for consumption.
Case studies 個案分析 (食物安全中心提供) • 3. If some products contain shell, should the shell be included in the calculation of nutrient content? • If the shell is usually removed before processing or direct consumption eg. Peanut, crab etc., the shell should be removed before analysis for the nutrient content.
Case studies 個案分析 (食物安全中心提供) • 4. Does Shiitake mushroom needs to remove stem before analyse? • Mushroom or fungi belongs to vegetable, and therefore it is exempted if no other ingredient is added or packed.
5. Tea and coffee are quite similar, can coffee bean or powder be exempted? • Case by case • If brewed coffee does not have any energy value or contain any contents of core nutrients, the prepackaged product could be exempted. • For “espresso”, both the energy value and protein content are unlikely able to meet the definition of “zero”.
Reasons for deviated test results of food nutritional test • 1. Sampling – tested sample randomly selected from production line. Batch to batch variation exists. • Test samples are not homogeneous. • 3. Raw material is different. • 4. Different test methods are used in analysis.
Price and time to do nutritional label • Generally, the price of “7+1” is HK$4500 include alcohol and organic acid. • It is about HK$3500 if alcohol and organic acid are excluded. • It takes about 15 working days to finish the “7+1” tests.
Thank You ! CONTACT: Secretariat1/F, CMA Building,64-66 Connaught Road Central, Hong Kong Tel : 25428664 Fax: 2541 8154 http://www.hktic.org/