Guest Columns

Perspective:
Dairy Technology

In-line analyzers aid precision, cost savings in dairy production

Troy M. Tillman

Troy M. Tillman is senior product manager for process analyzers at AMETEK MOCON, a provider of gas measurement, sensors and analyzers as well as testing services for barrier film, packaging and industrial applications. He is a guest columnist for Cheese Market News®.

Figure 1: Moving average protein/fat ratio calculated over approximately 14 cheese vat fills

Standardization of cheese milk is critical to maintaining quality standards for various cheese types, as well as maximizing yield, or economic return, for manufacturers. Different cheese types require different ratios of protein, fat and moisture, with guidelines either self-imposed or set by government standards. Complicating these requirements, milk composition can vary based on factors like season and nutrition, which means manufacturers must constantly monitor the various constituent levels to properly standardize the product.

While lab testing provides accurate data and is typically required as part of a quality control process, it doesn’t provide the real-time results and instant analysis that manufacturers need to maximize throughput. Luckily, many companies are now offering specialized technology in the form of dairy process analyzers, which provide an in-line solution to constituent analysis. Real-time results and better precision lead to cost savings and allow manufacturers to maintain a consistent product within specification.

• Challenges in Cheddar standardization

Standardization of cheese milk starts with identifying the composition of milk going into the cheese vat. The protein-to-fat ratio is set before or while filling the vat, either by adding or removing fat (cream) or casein protein (skim milk). Once the vat is filled, a sample is collected to be analyzed. If the ratio is incorrect, the product in the vat needs to be adjusted; since the vat filling time is short (typically around 20 minutes), production timing is critical.

As an added complexity, manufacturers may produce multiple products with different ingredient requirements on any given day in their facility. This can make it difficult to maintain the required fat-to-protein ratio for each type without sacrificing throughput.

For example, cheeses such as Cheddar and Monterey Jack must maintain ratios over a range of zero-fat, lowfat and regular fat options. The challenge is maintaining a consistent, in-specification protein-to-fat ratio in the vat, as well as vat-to-vat consistency between the same products.

In-line dairy analyzers can provide rapid results that facilitate real-time adjustments to the cheese milk going into the vat (see related graphic).

• The problem with processed cheese

Processed cheese is a blend of natural cheese and other ingredients such as oil, cream, anhydrous butter, salt and food coloring, in different ratios depending on the product. Each blend is tested for moisture and fat, then cooked with steam. Moisture is controlled during the steam process, and production managers ensure that products are within specifications.

Typically, processed cheese samples need to be collected and manually tested in a lab to keep the blend within specification. This analysis can take a long time, during which production is either stopped or continues with the risk of producing out-of-spec product.

Mozzarella spans a wide gamut of moisture content. Like processed cheese, Mozzarella cheese is cooked and stretched in hot water, and the moisture is checked by collecting samples as they exit the cooker. Those samples are also manually tested, but data can be unreliable because moisture is released as the sample is cut from the main block.

For both processed cheeses and Mozzarella, an in-line dairy analyzer provides better results, with the ability to average any free water as the product is flowing through the measurement point.

• The need for reliable results

Modern dairy analyzers give cheese manufacturers lab-quality results that don’t take hours and don’t increase the risk of human error. They place streamlined information right in the production manager’s hands, letting them make real-time adjustments if content ratios are off, even with multiple cheese types in simultaneous production. By relying less on cumbersome manual testing and more on real-time, accurate results, producers can reduce delays in their manufacturing process.

In some instances, in-line measurements are actually closer to the target value (via wet chemistry) than lab results.

• Comparing constituent analysis technologies

Most dairy analyzers on the market rely on one core technology: near-infrared spectroscopy, or NIRS. This spectroscopic method is used in a range of applications, including neuroimaging, sports medicine and pharmaceuticals, but it is especially useful for measuring properties in food products. By evaluating the energy absorbed by the vibrational frequencies of different molecules in the sample, NIRS can quantify the sample’s composition, including parameters like protein, moisture and fat concentration. NIRS analyzers may rely on one of two common techniques: reflectance and true transmission.

Reflectance NIR spectroscopy relies on an interface window installed onto the exterior of the production line. This technique uses reflectance to bounce light onto the product and back to the analyzer. Reflectance NIRS typically can’t capture a fully representative cross-section of the sample, which can lead to inaccurate data.

For example, a product like butter is susceptible to turbulent flow, which leads to variations in moisture and viscosity within the flow pipe. Reflectance NIRS can’t penetrate the full diameter of the flow pipe, resulting in lower-quality data. It also relies on reflective properties in the sample, which means it may not be optimal for certain clear products.

For high-quality and accurate data, many manufacturers rely on true transmittance NIRS. This approach to transmittance involves replacing a section of the pipe with a flow cell, ensuring a representative sample is monitored and analyzed. Light is transmitted through a fixed sample path, and the remaining energy not absorbed by specific constituent molecules is collected and analyzed. A larger sample cross section (typically 10-20 mm) also helps with data quality, providing facilities with the information they need to make fast and effective constituent adjustments.

With true transmittance NIRS, you’re receiving real-time, high-quality data that lets you make adjustments as soon as possible — even before production starts.

CMN

The views expressed by CMN’s guest columnists are their own opinions and do not necessarily reflect those of Cheese Market News®.

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