All dairy processing machinery needs to meet robust quality standards to conform with food safety and hygiene handling procedures. A minor change in the ratio of ingredients, temperature or operation times can have serious consequences. But why?
FTL Technology – suppliers of a wide range of mechanical split shaft seals, manufactured by MECO, told DairyReporter milk can be contaminated at any point in the milk production process and it is the responsibility of the milk producer to identify these points and implement control measures to protect milk from contamination.
The key sources of contamination in processing machines are:
- Bacteria from inadequately cleaned and disinfected equipment (including bulk milk tanks)
- Foreign bodies, especially from perished components in milking machines and bulk tanks, dust, bedding materials, dung, insects and animal hair.
- Chemicals, metals, organics, etc., from veterinary product residues, cleaning chemicals and use of non-food grade equipment.
When looking at sealing applications, FTL technology said, the STAMPS process is a good initial step to providing a sealing solution which is well suited to the unique demands of dairy applications. The STAMPS process considers the following factors: Size, Temperature, Application, Media, Pressure and Speed.
The size can be a limiting factor in the method of manufacture and can exclude some materials from the running.
Temperature is important in order to select the most appropriate material for all parts of the duty cycle. This includes typical running temperatures and any heat generated by friction on dynamic sealing applications, as well as overall minimum and maximum temperatures.
Application details typically include information relating to the duty cycle, outlining relative movement of interfacing parts, heating times, running times, cooling times and any known variables such as the thermal expansion of components during the process.
When selecting a sealing material, the media it comes into contact with is crucial. A detailed definition is required of the state (solid, powder, granules, flakes, slurry, liquid, gas) and any changes of state during the process. What’s more, the chemical makeup is important so a breakdown by % weight or volume of all key constituent parts aides with correct material selection.
Pressure is important for understanding the duty cycle as many applications switch between pressure and vacuum, which impacts on the dynamic forces acting on the seals.
Lastly, speed has a major part to play in material selection as many sealing solutions involve a dynamic interface between the seal and a shaft, spindle or stator.
What regulations are in place?
The EU food hygiene legislation, which came into effect on January 1, 2006, defines the duty of food businesses to produce food safely and to achieve consistency. It covers the whole food chain from farm to fork. Key elements of the previous dairy hygiene legislation were retained, such as hygiene during milking.
Milking must be carried out hygienically, ensuring during transport the cold chain must be maintained and, on arrival at the establishment of destination, the temperature of the milk and colostrum must not be more than 10°C.
The term ‘food safe’ is often used when deciding upon material suitability for dairy applications.
There is no universally adopted ISO standard in place to define what ‘food safe’ means, FTL Technology said. Nonetheless, the most prominent quality standards on this front are regulated by the Food & Drug Administration (FDA).
The FDA regulates the contents of foods, drugs, cosmetics and other potential consumables to ensure they are fit and safe to human use. Although the jurisdiction of the FDA is restricted to the US, FDA regulations are commonly adopted globally as the recognised control standards.
CFR21.177.2600 describes the relevant regulations for ‘rubber articles intended for repeated use’ so is important when selecting materials suitable for applications where a rubber seal comes into contact with dairy products.
FTL Technology said, however, it is crucial to note a ‘food safe’ material does not guarantee the seal’s safety as the method of manufacture and the environment in which the seal is manufactured can impact on the seal’s suitability for use in food contact processes.
FTL Technology said MECO dairy seals offer clean and cost-effective sealing solutions for wet dairy processes requiring a sanitary seal.
A variant of MECO’s popular AH model seal, the dairy seal is specifically designed to meet the needs of dairy product manufacturers by handling pastes and slurries including cheese, butter and dairy mixes.
Features of MECO Dairy Seals include: large radius corners to eliminate bacterial entrapment areas; no tools’ assembly and disassembly; fully-split and easy to remove, bench sanitize and reinstall; and optional threadless flush connections, seal-welded in place.
In dairy processing, FTL Technology concluded, companies need to take every precaution to ensure seals are manufactured from FDA compliant materials in a clean and controlled process environment. This will minimize contamination risk and give the greatest confidence that end products are fit for human consumption.