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Avoiding contamination when working with vacuum pumps

11 November 2019

Iain Cunningham argues that the industry needs to catch up when it comes to vacuum pumps in order to reduce machine downtime, maximise air quality and performance – and, most importantly, avoid the risk of food contamination. 

Avoiding a food contamination incident will be high on the list of priorities of all manufacturers in the food and beverage sector. Despite this, there is one area that is suffering due to a lack of knowledge about it – vacuum packaging. In many cases, supermarkets and other food retailers are well-informed about compressed air in food packaging, but lack knowledge about the vacuum process and are unsure of their responsibilities. If certain steps are taken, however, it is simple to ensure that vacuum pumps can minimise contamination risks and machine downtime, while maximising air quality and pump performance.

One of the outcomes a food producer will be keen to avoid is any negative impact on the company’s relationship with their customer. The key question in cases of food contamination is whether the retailer still trusts the manufacturer to supply food that will not harm their customers or their reputation with consumers. The competition among supermarkets is fierce and any reputational risk can send their share price sliding.

This is why rigorous audit procedures are put in place to provide the necessary reassurance that quality standards are being delivered. The more that food producers can do in providing that assurance, the more they can differentiate themselves from other suppliers. For the food manufacturer, any product recall or investigation has commercial implications. There is the cost of the batch recalls themselves as well as the lost production downtime to find any potential sources of contamination. For a food plant, every minute of lost production will have an impact on the bottom line.

Today, no questions are asked about how and why compressed air has the potential to contaminate food during the production process. As with many other packaging methods, the use of compressed air is covered within the hazard analysis and critical control point principles (HACCP), and everyone is clear about their responsibilities.

But that control is missing when it comes to vacuum packaging. However, with a forward-thinking, proactive and responsible approach, these risks can be virtually eliminated.

Contaminant threats
Vacuum sealing is most commonly applied to fresh, processed and frozen foods. The technique removes oxygen from the package holding the product and protects the contents from contamination or decomposition resulting from exposure to air, moisture or dirt. It ensures that taste, flavour, aroma and nutrition are not lost in the packaging process, and can extend the shelf life of food by up to five times. But it also risks contaminants – such as dust and droplets of oil – coming into contact with the food.

The majority of vacuum pumps are oil-lubricated – and this poses a challenge, as oil has the potential to contaminate food directly or find its way onto the employees working in the plant. As the vacuum pump sucks air out, it needs to exhaust somewhere. Air or oil separator filters are installed to capture the oil; however they are unable to completely remove the contaminant.

In some cases, due to a lack of servicing or issues such as badly fitting or failing separators, the filters can work less efficiently, resulting in an increase in oil carryover through the exhaust of the pump. Oil droplets then circulate in the air of the food environment, likely contaminating food. 

One solution is to move the machine away from direct contact with the production area, behind a wall or above a ceiling. Equally, basic processes such as cleaning and the environment around the machine are also important to the pump’s performance.

Avoiding the pitfalls 
The first way to ensure that you avoid the common pitfalls around vacuum pumps in food packaging is to fit downstream oil filters to act as a further safeguard against accidental food contamination from the failure of blocked filters. This will, in turn, prevent the carryover of oil into the environment.

Equally, it is often poor maintenance, or inadequate maintenance practices, and minor equipment faults that risk oil discharging from the exhaust and the potential for oil contamination from oil-lubricated vacuum pumps. This points to timely maintenance as an effective way to avoid potential contamination, ensuring that pumps run properly with little or no oil carryover and increases pump efficiency and pump life expectancy.

Even with a high level of care and due diligence, however, tiny amounts of lubricant can come into contact with a food contact surface, the packaging or the food itself. To legislate against this, choose food grade or incidental contact lubricants as they are specifically designed to meet strict regulatory limitations.

It is also important to always use genuine parts for pumps. Oil-lubricated vacuum pumps run the risk of oil being discharged from the exhaust and there is a chance the separator element may fail due to disuse, a poor fit or poor quality. Genuine parts will dramatically reduce the risk of this happening.

Finally, the ultimate way to avoid the issues associated with oil-lubricated pumps is to go oil-free. Specifically developed to meet the needs of manufacturers requiring only the highest air purity standards, oil-free pumps do not require the same level of maintenance as oil-lubricated models as there is no need to replace oil or filters. This also provides the added benefit of cutting down on costs over a pump’s lifetime. Oil-free pumps do not have to be removed to carry out maintenance so there is also a reduction in equipment downtime and associated costs from oil, waste old disposal or labour.

Iain Cunningham is food & beverage sector manager at Elmo Rietschle, part of the Gardner Denver Industrials Group. 

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