At the end of 2019, the US Department of Agriculture (USDA) had announced 34 recalls of 17 million lbs of meat and poultry products for the year, after “foreign materials” were found. Ten years before that, in 2009, there were five recalls of 1 million lbs of meat for what USDA calls “foreign matter contamination.”

How does it happen? Sometimes metal parts break off from the machines that mix and process the products. Other times pieces of rubber gloves come off plant workers’ hands. Plastic and glass from packages and containers can also end up in food products.

Why the dramatic increase? The speed of food production is increasing. Older processing equipment can break down. Consumers who find foreign objects in their food are not keeping quiet about it. They name company names and often publish photos of the contaminated food on social media. Eight years ago, reacting to Congress, USDA increased its reporting requirements. And furthermore, a year and a half ago, USDA published guidelines to prompt quicker processor response to reports of foreign contamination.

While some foreign matter is found by consumers when they’re eating, the industry is working to detect contamination long before the food is consumed.

“X-ray, vision and NIR (near infrared) technologies are available today,” explained Glenn Holliday, product specialist for detection equipment at Marel. “X-ray detects density, vision by shapes and colors and NIR by infrared sub samplings. X-ray is limited by any contaminate with a similar density to the meat – it will not be detected. Vision only sees what is on the surface of the product, not what is imbedded in it. NIR doesn’t scan the entire product, only takes sub samples and can miss contaminants because of the scan range.”

Holliday said the goal is to deliver to the customer end-of-line products that are 100% contaminate-free, although he admitted 100% is an unattainable goal. Marel’s products include X-Ray single lane and dual lane, and a three lane for smaller products, mainly used to find bones in poultry.

“In meat we have three different systems, the Magna, the Accuro and Omnia, looking not only for foreign contaminate, but fat analysis as well,” he said.

Bone detection can be difficult because of unrealistic expectations since cartilage bone is difficult to find. Holliday said there is a lot of pressure from processors for equipment to detect foreign material contamination.

“Definitely, the customers are demanding higher standards and sometimes demand specs that are not available yet,” he noted.

Eric Garr, area sales manager for Fortress Technology, said, “Metal detection is most common, since metal is the number one contaminant. But X-Ray can be used as a complementary technology to detect non-metal contaminants and provide fat analysis.”

Not only is metal detection the backbone of food safety compliance, it has made huge strides in accuracy and avoiding false positives, Garr said. “Today, metal detection can rival X-Ray in some of the toughest metal contamination challenges, with a far more affordable capital cost.”

Application flexibility

During the past year there has been more demand for faster, more versatile and hygienic inspection systems since meat and poultry processors are facing demands from retailers to provide products in different packaging styles and sizes. New technology can help processors of processed meats like patties or chicken strips.

“For meat processors handling high-viscous meats, the Fortress Meat Pump Pipeline metal detector is very good,” Garr said. “Our Interceptor metal detector conquers the challenge posed by moisture in meat and poultry and can be placed in different locations on a meat production and packing line,” he explained.

Kyle Knudsen, vice president of technology at ProSpection Solutions, pointed to automation as one reason for an increase in foreign material contamination in food.

“With automation, more processing equipment can break, and there are fewer people to catch it. More product being produced increases the chance that some of it contains foreign material. And more attention is being paid – more consumers are aware of the possibility of foreign objects in the products they consume,” Knudsen said.

Detection products from ProSpection Solutions include the Foreign Material Detection System for low density foreign material in a continuous product flow and Eliminator Grinder, which removes foreign material like bone while taking whole muscle to the final grind.

“Most of the meat industry is similar in terms of methodology in detecting foreign contaminants, and many of the companies producing equipment for this purpose sell to the entire meat industry,” he said.

There is pressure on meat and poultry processors to find contamination before their customers do. “Companies can suffer financial penalties for foreign contaminants, and can even lose customers because of it,” Knudsen said. “Our goal is to alert the facility that the foreign material was detected, so they can determine and resolve the cause.”

Overcoming inherent hurdles

In focusing on new technology in contaminant detection, David C. Smith, sales manager for Advanced Detection Systems, points to simultaneous multiple frequency metal detection units that have been designed to reduce the adverse impact of “product effect.”

“‘Product effect’ is a signal put out by the meat and poultry itself, that can make detection of particles harder,” Smith said. “Fresh meat makes it harder to detect contamination than dry products. These units reduce that impact.

“As metal passes through the oscillator and receiving coil, the current induced in the coil changes. This causes an imbalance, which is amplified and detected in the electronic control unit.”

Smith said Advanced Detection Systems engineers and manufactures conveyor mount and pipeline IP69K rated ProScan metal detection units for use in meat and poultry applications. The types of detection processors use depend on what type of meat and poultry products they are making.

“Those who have high risk for bone contamination readily adopt X-Ray technology. Meat processors with high risk associated with metal from knives and processing equipment tend to focus on metal detection,” he explained.

New technologies for detection of foreign matter contamination and other problems are moving through the industry, according to Chris Young, business development manager for Anritsu.

“They include X-Ray systems using dual-energy systems to better focus on detection of poultry bones. There are newer second-generation systems with advancements to minimize operating costs and increase detection performance.

“Metal detectors are now moving from single frequency to dual/multiple frequencies to increase capability,” he said.

Soft foreign material contamination can also be a concern.

“Soft contaminants are normally associated with lower-density contaminants – basically all non-metallic contaminants are considered ‘soft’ and that includes glass, stone and bones. Softer bones are harder to detect than beef or pork bones,” Young said. “We recently released our XR75 DualX Poultry system that has significant improvements in detection, sanitation and cost of ownership compared to our previous dual energy poultry system.”

He said Anritsu offers product control software allowing for real-time monitoring of production results. The number of products rejected, images of contaminated products and contaminants themselves can be monitored, analyzed, recorded and saved.

ContamPlus software on Mettler-Toledo’s X-Ray systems has improved ease of use for product setup and reduces false rejections, according to Lanel Menezes, business manager for the company’s Safeline X-ray division.

“The Profile metal detector utilizes the latest multi-simultaneous frequency technology by canceling ‘product signal’ caused by moisture or salt in the meat product, allowing detection of metal contaminants up to 50% smaller in size,” said Camilo Sanchez, product manager metal detection for Mettler-Toledo Product Inspection.

The company has packaged product inspection systems, equipment to inspect raw, unpackaged products, and a Looseflow system for raw, formed products like burger patties.

The detection of soft foreign materials, including chicken bones, can be done using the company’s X38 X-Ray pipeline system.