RTCR 460: 2011" Requirements for Sanitary Varnishes Utilizadas en Conservas de Productos Pesqueros" 1. PURPOSE The purpose of this Technical Regulation is to establish the requirements that must be met by the varnishes (barnices) that internally and externally coat the metal containers (envases) used for canned fishery products.
2. SCOPE OF APPLICATION It applies to all varnishes (barnices) that internally and externally coat the metal containers (envases) used for canned fishery products of national or imported origin that are marketed in the country. For the purposes of this Regulation, container (envase) shall be understood to mean the body and/or the ends (tapas).
3. REFERENCES This Technical Regulation is complemented by the following Technical Regulation: Executive Decree No. 36463, RTCR 443:2010 Metrology. International System (SI) Units of Measurement, published in La Gaceta No. 56 of March 21, 2011.
4. DEFINITIONS For the purposes of this Regulation, the following terms shall be understood to mean:
4.1 Adhesion (Adherencia): The force with which the internal and external coating varnish (barniz) adheres to the surface of the substrate (sustrato).
4.2 Autoclave (Autoclave): Pressure equipment intended for the thermal treatment of foods packaged in hermetically sealed metal containers.
4.3 Varnish (Barniz): A coating material that, when applied to a substrate (sustrato), forms a solid film after a polymerization process, acquiring specific technical properties and providing protection and appearance, being resistant to the autoclaving process.
4.4 Anchor varnish (Barniz de enganche): Varnish (barniz) applied directly onto the substrate (sustrato), to improve the adhesion of other varnishes in a multi-layer system.
4.5 Organosol varnish (Barniz organosol): Super flexible sanitary varnish (barniz sanitario), a dispersion of PVC in an organic polymer.
4.6 Side-seam protection varnish (Barniz de protección de costura): Varnish (barniz) applied in the side seam zone, which may be liquid or in powder form.
4.7 White porcelain sanitary varnish (Barniz sanitario blanco porcelana): Varnish (barniz) with white pigment for the interior coating of the body, end (tapa), and bottom of metal containers (envases).
4.8 Aluminum sanitary varnish (Barniz sanitario de aluminio): Varnish (barniz) with aluminum paste for the interior coating of the body, end (tapa), and bottom of metal containers (envases).
4.9 Gold sanitary varnish (Barniz sanitario dorado): Gold-toned varnish (barniz) for the exterior and interior coating of the body, end (tapa), and bottom of metal containers (envases).
4.10 Colorless sanitary varnish (Barniz sanitario incoloro): Colorless varnish (barniz) for the exterior and interior coating of the body, end (tapa), and bottom of metal containers (envases).
4.11 Curing (Curado): The final state of polymerization of a varnish (barniz), achieved at the temperature and time established in its technical data sheet.
4.12 Container (Envase): Any metal container with its ends (tapas) intended to hold a product and which must be closed hermetically, preserving its physical, chemical, and sanitary integrity after sterilization in an autoclave.
4.13 Canning establishment (Establecimiento Enlatador): An establishment dedicated to the production of canned products in tinplate containers (envases de hojalata).
4.14 Varnish film weight (Gramaje de la capa de barniz): The amount of varnish coating considering a single layer or a multi-layer system expressed as an average weight per area.
4.15 Varnish film fracture (Fractura de la película de barniz): A discontinuity in the varnish film, the depth of which reaches the substrate (sustrato), allowing contact between the substrate and the packaged product.
4.16 Varnish film (Película de barniz): Coating material that, when applied to a substrate (sustrato) in one or more layers, forms a solid film that has specific technical properties providing protection and/or appearance.
4.17 Porosity: The presence of visible cavities produced due to the heterogeneity of the varnish in a single-layer film. Contact between the food and the substrate may occur in these pores.
4.18 Substrate (Sustrato): The metal sheet onto which the varnish film is applied and from which the containers (envases) and ends (tapas) are manufactured.
5. SYMBOLS AND ABBREVIATIONS For the purposes of this Regulation, the following shall be understood to mean:
5.1 GT: Adhesion grade (Grado de adherencia) between the varnish film and the substrate.
5.2 dm2: Square decimeter.
5.3 m2: Square meter.
5.4 %: Percentage.
5.5 g: Grams.
5.6 mm: millimeter 6. SPECIFICATIONS AND REQUIREMENTS:
6.1 The interior varnish (barniz interior) must be harmless to humans.
6.2 The interior varnish (barniz interior) must have a homogeneous appearance, meaning it must not show fractures, detachment, or visible deterioration.
6.3 The exterior varnish (barniz exterior) must have a homogeneous appearance, meaning it must be uniform and well adhered.
6.4 The adhesion evaluation scale is determined by visual observation as established in the following table:
| Class or GT | Detachment or visible lack of adhesion | | --- | --- | | 0 | Shows no detachment or lack of adhesion. | | 1 | Affected area < 5% with loss only at intersections or edges. | | 2 | Affected area between 5% and 10% loss at the intersection and in the cut. | | 3 | Affected area between 10% and 25% varnish loss affecting the intersections and edges, with detachment in some squares. | | 4 | Affected area between 25% and 50% with complete loss of adhesion in many squares. | | 5 | Affected area > 50% with extensive varnish detachment. | Note 1: The adhesion evaluation scale indicated in point 6.4 corresponds to a visual evaluation carried out by trained personnel.
6.5 The adhesion of the varnish (barniz), both interior and exterior, to the substrate (sustrato), prior to manufacturing the container (envase) or end (tapa), must be a maximum of Class 1 (GT1).
6.6 The adhesion of the powder side-seam protection varnish (barniz de protección de costura en polvo), may have a maximum of 3 mm, before the autoclaving process.
6.7 For the adhesion of the liquid-applied side-seam varnish (barniz de costura), a maximum adhesion of Class 2 (GT2) is considered acceptable, before the autoclaving process.
6.8 The porosity of the varnish (barniz) must be less than or equal to 0.04 pores per dm2 (4 pores per m2), on the metal sheet before forming the container (envase) or ends (tapas).
6.9 The varnish film weight (gramaje del barniz) per unit of surface area that coats the substrate (sustrato) for the interior of the container (envase), must meet at least the following values:
6.9.1 Single-layer interior varnish (barniz interior) ≥4 g/m2.
6.9.2 Anchor varnish on sheet ≥2g/m2.
6.9.3 Organosol varnish ≥8 g/m2.
6.9.4 White or porcelain interior varnish (barniz interior) ≥9 g/m2.
6.9.5 The mass of the varnish (barniz) coating the substrate (sustrato) for the exterior of the container (envase) must be ≥4 g/m2.
The preceding values shall be verified through on-site audits at fishery product canning establishments (establecimientos enlatadores) by means of the certification of parameter compliance by the container supplier.
The preceding values may be additionally expressed in other equivalent units. Furthermore, they may change due to technological advances in varnishes (barnices), which must be technically justified with the specification established by the varnish supplier in the technical data sheets.
6.10 The film weight (gramaje) of the varnish (barniz) that internally and externally coats the metal sheet to manufacture the container (envase), end (tapa), or bottom must be determined by a method validated by the container supplier company, which shall be verified through a documentary audit at the canning establishment (establecimiento enlatador).
6.11 The curing of the varnish is determined by a method validated by the container supplier company, verifying that it does not suffer visible deterioration and maintains its homogeneous appearance, within the range of temperatures necessary for the manufacture of the metal container (envase) and for the processing of the canned product. The curing shall be verified through a documentary audit at the canning establishment (establecimiento enlatador).
7. VERIFICATION This Regulation shall be verified by the National Animal Health Service of the Ministry of Agriculture and Livestock, by means of the verification of establishments processing canned fishery products in compliance with the provisions of this Regulation and the legislation granting it authority, and with the internal procedures established by SENASA.
8. CONCORDANCE This Technical Regulation does not concur with any international standard.
9. BIBLIOGRAPHY 9.1 Mexico. Dirección General de Normas. MMX-EE-147-NORMEX-2004 Packaging and packing-metals- Sanitary tinplate containers for food- Determination of the varnish layer- Test method. 2004.
9.2 Switzerland. International Organization for Standardization. IS0 2409:2007 Paints and varnishes. Cross-cut test. 2007.
9.3 USA. ASTM D 3359 Standard Test Methods for Measuring Adhesion by Tape Test. 2009.