Tips to optimize your grinding operation

Tips to optimize your grinding operation
By Ana Elia Rocha McGuire on 7/1/2008

Particle reduction is the basic technology for producing many meat products. During the process of grinding meat, many factors affect quality and must be controlled. These factors include the quality of raw materials, temperature during processing and equipment maintenance.

Although it won't be covered in this article, it's important to remember that good practices, hygiene and sanitation are extremely important during the production of ground products, and should always be executed and monitored.


Use high-quality raw materials.
To obtain a good product, it is necessary to use high (or acceptable)-quality meat, fresh and cold, with high water-retention capacity. Hamburgers made with Utility-grade pieces (the lowest-quality meat according to USDA) were less accepted by consumers than those made with Choice quality meat from the chest. Avoid using meat with a pH under 5.5 and a pale or discolored appearance.

Although not always practical in today's grinding operations, pre-rigor meats are considered excellent for yielding high-quality finished products, and should be an option.

Since it is softer than muscle, fat content in the meat can affect the efficiency of bone-removal systems in the grinders. The source of fat must also be considered. Pork fat is softer than beef fat at the same temperature because they have different degrees of unsaturation. So, when pressure is developed during grinding, pork products are more susceptible to smearing. To avoid this, pork grinding should be handled at slightly lower temperatures than beef grinding. One study suggested that a different bone-removal system design might be better for beef as opposed to pork products, and for high-fat as opposed to low-fat mixtures.

Other factors that affect product quality are the amount of bone chips, cartilage and connective tissue, too much of which may result in consumer rejection.


Keep a low temperature during grinding.
Temperature is always a control measurement in meat processing, both from a qualitative and microbiological standpoint. Given that, it is critical to try to use meat at a temperature of 28 degrees F or lower. Usually the temperature of the system rises a couple of degrees after grinding, making the meat more prone to microbial proliferation, but if you start with very cold meat, you should be fine.

Also, meat temperature affects equipment performance during grinding. A study investigated the effect of meat temperature, particle size and grinding systems on removal of bone chips from ground beef. It was observed that cold grinding temperatures (28 degrees F) resulted in a higher percentage of bone chips removed by the bone-removal system compared to higher grinding temperatures (38 degrees F).


Maintain equipment in good condition.
Since grinding meat results in more exposed surface, those meat components prone to oxidation — fat and myoglobin, for example — are then more susceptible to changes, because they are exposed to oxygen and catalysts. As grinder parts wear with use, the equipment shears less and smears more, increasing the exposed surface area of the meat even more. Increased friction raises the processing temperature of fat and myoglobin, promoting an even greater level of oxidation.

In a study of the effects of meat grinder wear on oxidation in fresh pork sausages, worn grinder hardware caused greater myoglobin oxidation in the sausages after frozen storage than sharp hardware. Worn hardware also caused greater grinding temperature increases than sharp equipment.

Therefore, equipment blades and plates must be perfectly sharpened and kept in good condition. Keeping grinder blades sharp will maintain a high-quality grind. This will allow proper contact between knife and plate across the cutting surface.

It is important to note that a new or newly sharpened part should never be put with another part that is worn. Mismatched sets will result in premature failure of both parts.