The Food Safety Modernization Act (FSMA) was signed into law in 2011 to prevent the health and economic impacts of badly processed foods. Current Good Manufacturing Practices (cGMPs) under FSMA CFR Title 21 117.40 is the cornerstone of this effort. Title 21 details the cleanability and cross contamination standards that plants must meet so that food is deemed safe and companies avoid recalls.
Cleanability and cross contamination prevention features as detailed by FSMA and cGMPs should be strongly considered when purchasing new equipment, but what about the current installed base of older systems? How do plants cost effectively and quickly upgrade these older systems?
Reduce contamination through better component selection
There are many potential sources of contamination in food production. Some of these issues can be eliminated through employee training, but some are inherent to the design of the machine. Furthermore, the components used in the equipment must meet wear and cleanability standards to maintain the utmost in food and packaging safety.
Unlike complete pieces of equipment, many electromechanical components are relatively cost effective to audit and replace as required to improve food safety. Here are eight steps for improving air quality and reducing potential sources of biologic, allergen, and particle adulteration:
Ensure compressed air does not contaminate food
Ambient air contains a host of impurities and in food plants adulterating and allergenic particles are added to the mix. Compressed air systems that are used in direct food contact and in motion control increase the density of these contaminants. It is vital that compressed air intended for direct contact with food and used at the end of the packaging line is made as clean as possible through filtration. For this reason, air filtration efficiency is the first line of defense for maintaining food safety.
However, cGMPs under CFR Title 21 117.40 do not define a required compressed air quality for direct contact with food and primary packaging, which means the required filtration level must be determined by the end user. While many end users have determined their own air quality requirements, others may be unsure of recommended purity. Organizations such as British Compressed Air Society (BCAS), 3A Sanitary Standards, VDMA Mechanical Engineering Industry, and Safe Quality Food (SQF) have published recommendations for specific air quality requirements. SQF recommends, for example, a final filtration stage of 0.01 micron with a filtration efficiency of 99.999% to be located at the point of use for direct food contact. If a plant has not created its own risk assessment, operations personnel may consider meeting the SQF standard.
The compressed air preparation unit has a filtration cascade meeting SQF. Assuming 7:4:4 air quality from the compressor, the resulting air quality of 1:4:2 also meets the ISO 8573-1:2010 standard that specifies purity classes of compressed air with respect to particles, water, and oil.
Evaluate additional potential contamination points with compressed air
While compressed air intended for food contact is often addressed with proper filtration, there are several additional ways that compressed air can come into contact with food. For example, leaking fittings and tubing will allow compressed air to exhaust in unexpected areas, which can often include areas directly over the food production. This means not only checking air nozzles and cylinders, but also finding and stopping leaks.
Preventive maintenance in terms of ongoing leak detection makes food safety and operational sense, i.e. leak detection lowers the risk of indirect contamination and reduces energy costs. The Festo MSE6-E2M module is an automated component for detecting leaks in a machine. Once a baseline of air usage is developed, the E2M module alerts plant personnel when too much air is consumed. This module also automatically lowers pressure when a machine is idle to further save energy. By monitoring compressed air usage, leaks can often be discovered soon after they occur and prevent potential contamination issues.
Another unintentional contamination source is the exhaust from valves controlling pneumatic components. Often, valves are mounted near or above the food zone, and the air exhausting from the valve therefore poses a contamination hazard. Distance exhaust as much as possible from food and packaging and eliminate leaks that may blow contaminants into the atmosphere. If the valve cannot be moved, then the exhaust should be ducted to a safe area.
Besides air being exhausted from a valve, a quick exhaust located on a pneumatic actuator will also vent compressed air. As quick exhausts are generally mounted to the actuator that controls part of the process, this means quick exhausts are generally exhausting near the food zone. Quick exhausts should be avoided if possible by installing the controlling valve closer to the application. By utilizing an IP69K valve manifold such as the Festo MPA-C, the tubing lengths can be significantly reduced, which improves machine speed and often eliminates the need for a quick exhaust. If quick exhausts still are required, the exhaust should be ducted to a safe area.
Ensure that pneumatic tubing is FDA-approved and resistant to cleaning processes
Plastics and elastomers that come into direct contact with food must comply with the directives of the FDA. The material must not give off or absorb any hazardous substances. Plastics and elastomers must also resist stress and be cleanable. Pneumatic tubing is at risk from various environmental influences as shown by the microscopic crack in the micrograph – a crack that can house contaminants.
Approximately 90% of the defects on pneumatic tubing are traced to chemical, microbiological, or physical influences. Proper tubing selection and upgrade can minimize or eliminate failures due to these influences. Hydrolysis-resistant polyurethane, PUN-H, and Polytetrafluoroethylene, PTFEN, tubing from Festo are ideally suited for use in the food industry. Both are resistant to cleaning agents, microbes, and hydrolysis and are FDA compliant. PUN-H is more flexible and economical, while PTFEN is ideal for the harshest environments.
Eliminate fittings that are difficult to clean
Exposed threads provide the perfect breeding ground for contaminants as the small spaces between the threads are difficult to clean. Any threads that cannot be avoided should therefore be closed off with suitable blanking caps and sealed.
There are several thread types used in pneumatic connections. BSPP, also known as G-thread, left in the image below, is a parallel thread that features a clean design that eliminates exposed threads by sealing flush to a gasket. Utilizing G-threads wherever possible is an easy choice for improved FSMA compliance.
Tapered threads such as R-thread and NPT, center and right, seal by wedging threads together and through the use of sealing tape. These tapered threads risk contamination, not only through exposed threads, but also from metal fragments or flaking tape. For this reason, tapered threads should be avoided for equipment in the food industry.
Eliminate components that corrode easily
Many potential sources of contamination in food production such as bacteria, chemical influences, or corrosion particles can be eliminated by utilizing a few basic design considerations. To ensure that cleaning is safe, the materials used must not react with the cleaning agents or disinfectants. Machine parts must be resistant to corrosion and be mechanically and chemically stable. The image below shows the incorrect choice of materials for a pneumatic cylinder based on the amount of corrosion.
Contrast the components above with the actuator made of stainless steel shown at left. Its design rigorously conforms to cGMP criteria. For example, there are no threads on the bearing cap and thus a reduced possibility of trapping contaminants. Its self-adjusting end position cushioning system is designed without contaminant susceptible adjusting screws. The actuator also utilizes NSF-H1 grease and FDA approved seals.
Ensure components can be easily cleaned
Small radii and corners pose a hygiene risk because flow velocities of the cleaning agents and disinfectants are substantially reduced in tight spaces and the required cleaning effect isn’t achieved. Components should have a minimum radius of 3 mm on parts as the illustration (right) shows.
A high gloss surface finish is essential on components that come into contact with the food product in order to reduce microbial contamination. This can be achieved by using a mean peak-to-valley height of 0.4 to 0.8 μm within the food zone. High-quality surface finishes and large radii, such as those found on the pneumatic actuator shown below, make cleaning the actuator quick and easy.
Vérin ISO aux dimensions conformes à la norme ISO 15552. Graisse NSF-H1 et matériau conforme FDA pour le joint même dans le modèle de base. En option avec système d'amortissement de fin de course autoréglable PPS et joint anti-marche à sec.
Toutes les machines et tous les composants du système doivent être conçus pour éliminer les espaces morts. Les restes de produit dans les espaces morts sont difficiles, voire impossibles à éliminer. Les composants doivent donc être conçus pour être soit complètement ouverts, soit complètement scellés, comme indiqué sur l'illustration de droite.
Les processus de nettoyage utilisent souvent des tuyaux à haute pression. L'équipement et les composants doivent être conçus pour résister à ces processus. Des surfaces résistantes et une classe de protection IP élevée, telles que le terminal de distributeurs Festo MPA-C IP69K, sont conçues pour fonctionner efficacement dans des environnements difficiles.
Assurez-vous que les actionneurs utilisent une graisse sans danger pour les aliments
Les États-Unis ont les réglementations les plus strictes sur l'utilisation des lubrifiants et des additifs utilisés dans l'industrie alimentaire. Les graisses et huiles lubrifiantes doivent être conformes au CFR 21 178.3570. Pour les équipements et composants qui entreront inévitablement en contact occasionnel avec des aliments et des emballages primaires, des lubrifiants approuvés tels que NSF-H1 doivent être utilisés.
Un contaminant alimentaire potentiel souvent négligé est le lubrifiant des cylindres pneumatiques. Un examen attentif dans la zone d'emballage montre parfois que de la graisse dangereuse fuit en fait du nez des bouteilles sur les aliments ou l'emballage primaire. Il est impératif de vérifier les cylindres pour la graisse NSH-H1 et de remplacer ceux qui n'en ont pas.
Dans la zone de lavage, un nettoyage intensif peut éliminer la graisse lubrifiante du cylindre. Non seulement cela pose un problème de contamination, mais cela nuit également au fonctionnement du cylindre. Dans la zone de lavage, utilisez des vérins dotés de joints fonctionnant à sec approuvés par la FDA, tels que le joint Festo A3. Cela garantira un fonctionnement propre et optimal même lorsque la graisse a été lavée du cylindre. L'élimination de l'utilisation de composants qui échouent parce que la lubrification peut être lavée est un exemple de la façon dont la nettoyabilité et les cGMP peuvent améliorer la disponibilité.
Réaliser des audits à intervalles réguliers
Les systèmes pneumatiques ne sont pas statiques. Les composants s'usent et les vibrations peuvent desserrer les raccords. De nouveaux composants deviennent disponibles qui sont non seulement plus faciles à nettoyer, mais aussi plus robustes et plus performants dans les environnements difficiles. Il n'est pas rentable de remplacer chaque machine plus ancienne, mais il vaut la peine en termes de fonctionnement propre et d'efficacité globale de l'équipement (OEE) d'entretenir et de mettre à niveau les composants pneumatiques et d'automatisation grâce à des audits réguliers.
Le principe d'organisation de ce livre blanc était de tracer l'air comprimé dans, à travers et hors du système pneumatique.
Chaque élément clé du système peut soit ajouter à un environnement sûr pour les aliments, soit le réduire. Utilisez cette disposition de début, de milieu et de fin pour organiser des audits de systèmes pneumatiques.
Festo propose une collection de supports pédagogiques téléchargeables sur la conception sanitaire dont les équipementiers et les utilisateurs finaux peuvent bénéficier. Les liens vers ces documents se trouvent sur www.festo.com/foodsafety
(1) Capturing Recall Costs: Measuring and Recovering the Losses, GMA - octobre 2011
(2) America’s food industry has a $55.5 billion safety problem. Forbes - 6 mai 2016