Could Peanut Butter Recall Due to Metal Contamination Have Been Avoided?

Out of an abundance of caution, a major peanut butter company recently voluntarily recalled over 150,000 pounds of peanut butter spread due to the possibility that a limited number of jars may have contained a small fragment of stainless steel from a piece of manufacturing equipment. The manufacturing facility’s internal detection systems identified the concern, but the company did not want to risk potentially compromised product reaching consumer hands.

It looks like the company certainly did have the consumer’s health in mind. First, they are using food safety equipment in the production facility, and second, they notified the public of the potential issue as soon as it was discovered. There were no consumer complaints associated with this voluntary recall prior to the press release, and all retailers that received the affected product were properly notified. And the recall is being conducted with the knowledge of the U.S. Food and Drug Administration. They even have a consumer engagement team that one can contact for instructions and information.

So how do these issues happen in the first place?

Physical contaminants can appear at almost any time during the food production process. According to the American Peanut Council, peanuts are the seeds of an annual legume, which are planted in sandy soil, grow close to the ground, and produce its fruit below the soil surface. When it’s time for harvesting, “a digger loosens the plant and cuts the taproot. A shaker lifts the plant from the soil, gently shakes the soil from the peanut pods and inverts the plant…. After drying in the field for two or three days, a peanut combine (also known as a thresher) separates the pods from the vines, placing the peanut pods into a hopper on the top of the machine. The vines are returned to the field to improve soil fertility and organic matter. Freshly harvested peanut pods are then placed into drying wagons for further curing, with forced hot air slowly circulating through the wagons.”

You can see how there could be plenty of opportunities for broken pieces of equipment to contaminate the supply of peanuts. And we didn’t mention that there’s the possibility that pieces of metal buried in the ground were dug up along with the peanuts.

The raw materials are then shelled, roasted, blanched, ground up into a paste, and packaged.

There are many types of equipment to accomplish these tasks, and it’s not uncommon for pieces of screens, worn parts, and screws, to break off and fall into the production line and into the food itself. (We address this in more detail in Where are the Risks for Contamination in a Food Processing Plant?)

Food manufacturers have two lines of defense against foreign object contamination: Industrial food metal detectors and X-ray inspection systems. However, certain foods are better inspected by certain equipment. (See the white paper: What food processors should know: metal detection vs. X-ray inspection.) We believe the better choice for inspecting dense creamy packaged food like peanut butter is the latest multiscan metal detection technology.

The type of food safety equipment used in this particular processing plant was unclear, but we do know that even if common single-frequency metal detectors were used, there can be barriers to achieving 100% metal-free products. The metal detector must find anything, anywhere in any product all the time. That can be daunting considering the volume of production from just one line in a day and all the different types of metal pieces that might contaminate the line.

Metal detectors use electromagnetic fields to find things that are magnetic and conductive. Most food products are wet, have salt or contain minerals which when subjected to electromagnetic fields also look magnetic and conductive. Ignoring the product and finding the metal is not as easy as it seems. In addition, small metal foreign objects have very small signals and the metal detector is operating in a factory that has many possible noise sources that can confuse the metal detector electronics and software.

Most stainless steel, which was the contaminant in the above-mentioned case, contains only a small amount of ferrous metal, has little or no magnetic property. To find stainless steel with a metal detector requires running a high frequency because the high frequency field induces a current in the stainless steel which creates a new field that interacts with the original field in the metal detector to create a signal.

It is for these reasons, that we would recommend using multiscan metal detectors, which are capable of scanning up to five user-selectable frequencies running at a time, offering one of the highest probabilities of finding ferrous, non-ferrous, and stainless steel metal contaminants. A multiscan metal detector enables the operator to pick a set of up to five frequencies from 50 kHz to 1000 kHz and the technology enables the equipment to scan through each frequency at a very rapid rate, effectively acting like five metal detectors in one. The result is that the probability of detection goes up exponentially and escapes disappear. Sensitivity is optimized since you also have the optimal frequency running for each type of metal of concern.

According to the American Peanut Council, “U.S. Peanut farmers produce around 3 million tons of peanuts annually on approximately 1.5 million acres … and Peanut butter, which by law must be 90% peanuts, is the leading use of peanuts produced in the U.S.” Food safety technologies, like multiscan metal detection, help ensure there are no metal contaminants in that remaining 10 percent.

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