Overview
ISO/TS 9941:2005 is an essential technical specification developed by the International Organization for Standardization (ISO) and the International Dairy Federation (IDF). It outlines a precise spectrometric method for determining the tin content in canned evaporated milk products. This method offers a reliable and standardized procedure specifically designed to detect tin concentrations at or above 5 mg/kg within milk samples. As tin contamination can pose health risks and affect product quality, this standard plays a critical role in ensuring food safety and regulatory compliance within the dairy industry.
Key Topics
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Scope and Purpose
The specification applies strictly to canned evaporated milk, detailing a robust method to quantify tin, an element that can leach from packaging materials or processing equipment.
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Principle of the Method
The test involves mineralizing the organic milk material with nitric and sulfuric acids, followed by complexation of tin using quercetin. The final absorbance is measured at 437 nm via spectrometry, enabling quantification of tin in the sample.
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Limit of Determination
The method detects tin at concentrations as low as 5 mg per kilogram of evaporated milk.
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Reagents and Apparatus
The procedure specifies the use of pure, tin-free reagents, such as nitric acid, sulfuric acid, quercetin, and specialized standard tin solutions, alongside precise laboratory instruments including calibrated mineralization flasks and a spectrometer with 10 mm path length cells.
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Sample Preparation and Testing
Samples must be carefully prepared to prevent contamination, heated in controlled water baths, and mineralized before spectrometric analysis. The method includes detailed steps to ensure accuracy, such as masking interfering ions and verifying tin recovery.
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Calculation and Reporting
The tin concentration is calculated and reported as milligrams of tin per kilogram of evaporated milk, ensuring consistent and clear communication of results.
Applications
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Quality Control in Dairy Production
Dairy manufacturers utilize this method for routine testing of evaporated milk products to ensure compliance with food safety standards and packaging regulations.
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Regulatory Compliance
Food safety authorities may reference ISO/TS 9941:2005 to verify tin levels and assess potential risks from metal contamination in canned milk products.
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Research and Development
Laboratories engaged in product development can employ this spectrometric method to monitor tin exposure during processing and packaging improvements.
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Packaging Material Testing
The standard aids in evaluating tin leaching from cans and other packaging, facilitating safer material selection by packaging engineers.
Related Standards
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ISO 3696:1987 – Specifies the quality of water for analytical laboratory use, which ISO/TS 9941 references for reagent preparation.
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ISO 707 / IDF 50 – Provides guidelines on sampling milk and milk products, essential to ensure representative test samples for accurate tin determination.
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ISO/TS 9940 – Covers related analytical methods for detecting minor components in milk and milk products.
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ISO Standards on Food Safety and Metal Contamination – Various ISO standards address limits and analysis of heavy metals in food items, which complement requirements for tin testing.
This specification is critical for maintaining the safety, integrity, and quality of evaporated milk by providing a scientifically validated and repeatable method for tin content analysis. Its adherence supports consumer protection and facilitates international trade compliance within the dairy sector.