- Many civilizations have relied on nuts as part of their diet, even before the usage of cereal grains. Nuts come from a variety of botanical families and serve as a reliable and timely food source because they are resistant to damage by severe weather, are easily preserved through long winters to ensure a stable food supply, and provide essential fatty acids, protein, and important micronutrients.
- Between 2000 and 2020, at least 1 nut butter-associated outbreak was reported to CDC’s National Outbreak Reporting System (NORS), causing 6 illnesses, 1 hospitalization, and no deaths.
- Between 2000 and 2020, at least 8 peanut butter-associated outbreaks were reported to CDC’s National Outbreak Reporting System (NORS), causing 1,627 illnesses, 309 hospitalizations, and 9 deaths.
- One of the most recent recalls occurred in 2019 due to Listeria monocytogenes which has ended.
- Nut butters have been associated with Salmonella outbreaks, especially Salmonella Bredeney and Typhimurium; a very large outbreak in 2010 was associated with peanut paste used in a wide variety of food products.
- The U.S. is the world’s third largest peanut producer, following China and India. The state of Georgia has the largest peanut production in the U.S., followed by Texas.
- Research studies have linked nut consumption with reduced heart disease and gallstones in both genders and diabetes in women. There is also evidence pointing towards easing hypertension, cancer, and inflammation.
The term ‘nut butter’ is a generic name for any spreadable food product made from crushed or blended nuts. The six most common nuts used in making nut butter are almond (Prunus dulcis) from the Rosaceae plant family, cashew (Anacardium occidentale) from the Anacardiaceae family, hazelnut (Corylus avellana) from Betulaceae family, peanut (Arachis hypogaea), and soybean (Glycine max), both from the Fabaceae family. Peanut production is primarily focused in three major geographic areas of the United States: the Southeast (Alabama, Florida, Georgia, Mississippi, South Carolina), the Southwest (New Mexico, Oklahoma, Texas), and Virginia and North. The United States is the leading producer of almonds, accounting for 68% of the world’s almond production. They are mainly grown in central California. Ninety-nine 99% of hazelnut production is found in Oregon. From 2007 to 2011, hazelnut production has fluctuated but has steadily climbed to over 40,000 tons. In recent years, tree nut consumption in the U.S. has averaged 3.69 pounds per person, which is greater than past intake, potentially due to increased output of tree nuts. The large influx of imported tree nuts, such as cashews, accounted for 33% of all tree nut consumption from 2007 to 2008.
Foodborne Outbreaks and recalls.
Between 2000 and 2020, at least 1 nut butter-associated outbreak was reported to CDC’s National Outbreak Reporting System (NORS), causing 6 illnesses, 1 hospitalization, and no deaths. Between 2000 and 2020, at least 8 peanut butter-associated outbreaks were reported to CDC’s National Outbreak Reporting System (NORS), causing 1,627 illnesses, 309 hospitalizations, and 9 deaths.
One of the most recent recalls occurred in 2019 due to Listeria monocytogenes which has ended. Oskri Organics recalled all nut butters due to positive test results of Listeria. There were no ill cases. Salmonella had been associated with the following nut butter outbreaks:
2017: A multistate outbreak of Shiga toxin-producing Escherichia coli O157:H7 was linked to I.M. Healthy Brand SoyNut butter. Twelve states in the US were invlolved with 32 people incfected, no deaths, and 12 hospitalizations. Of the 32 people infected, nine people developed hemolytic uremic syndrome. The SoyNut butter was recalled which was eventually terminated.
2015: Between July and November 2015, 13 people were infected with the outbreak strain Salmonella Paratyphi B variant L(+) tartrate(+) across 10 states. No hospitalizations or deaths were reported in association with the outbreak. Investigation into the outbreak found the JEM Raw brand of sprouted nut butters was the most likely source, leading to the JEM Rasw Chocolate brand issuing a voluntary recall of all sprouted nut butter spreads that were both sold in stores and mail ordered.
2014: In August of 2014, almond and peanut butters, packaged in glass and plastic jars under various brand labels, were recalled because of potential contamination with Salmonella. CDC reported a total of six persons were infected with the outbreak strain of Salmonella Braenderup since January 1, 2014: one in Connecticut, one in Iowa, one in New Mexico, one in Tennessee, and one in Texas. While one ill person was hospitalized, no deaths were reported.
2012: CDC collaborated with public health officials in several states and the U.S. Food and Drug Administration (FDA) to investigate a multi-state outbreak of Salmonella Bredeney infections from Trader Joe’s Valencia Peanut Butter, manufactured by Sunland, Inc. of Portales, New Mexico. DNA ‘fingerprints’ of Salmonella bacteria from Pulse-Net, the national sub-typing network that performs molecular surveillance of foodborne infections, were used through diagnostic testing with pulsed-field gel electrophoresis (PFGE) to identify the bacteria that were part of this outbreak.
According to the CDC, a total of 42 people were infected with the outbreak strain of Salmonella Bredeney from 20 states; 68% were children under the age of 10 years, 59% were male, 28% were hospitalized, and no deaths were reported.
2008: Between September 2008 and March 2009, a multistate outbreak of Salmonella Typhimurium occurred across 46 states and infecting 714 persons. Among infected persons, 24% were hospitalized and nine deaths were reported. The first national case-control study conducted Collaboration between the CDC and public health authorities compared foods consumed among ill versus well individuals, identifying peanut butter as the most likely source. Investigation by several state health departments identified the King Nut brand peanut butter produced by the Peanut Corporation of America, a nationwide distributor of peanut butter and peanut paste to institutions, food service providers, food manufacturers and distributors. The recall of PCA peanuts and peanut products totaled with 3,913 different products made by 361 companies. In September 2014, the CEO of PCA, Stewart Parnell, and his brother Michael Parnell were convicted of over 70 criminal counts linked to intentionally shipping out contaminated peanut products. Steward Parnell was sentenced to 28 years in prison, while Michael Parnell was sentenced to 20 years.
2007: Public health officials in multiple states, CDC, and FDA investigated a large multi-state outbreak of Salmonella Tennessee (serotype) infections. An epidemiological study was executed comparing ill and well persons that ate Peter Pan peanut butter and Great Value peanut butter, and it was concluded that both products were likely the source of the outbreak. Product testing confirmed the presence of the outbreak strain of Salmonella Tennessee in opened jars of peanut butter obtained from ill persons. Consumers were alerted not to consume peanut butter with a product code beginning with 2111. CDC reported 425 persons infected with the outbreak strain of Salmonella Tennessee in 44 states. Of 351 patients for whom clinical information was available, 71 (20%) were hospitalized. No deaths were attributed to this outbreak.
2004: An outbreak of Salmonella Enteritidis occurred in 12 U.S. states and in Canada from Paramount and Raw Almonds. Traceback investigation found that the initial five patients infected all reported consuming Kirkland Signature brand almonds; later interviews with 26 patients further found that 20 patients consumed almonds packaged or supplied by Paramount Farms, including the Kirkland Signature brand. Paramount Farms issues a nationwide recall of all raw almonds under the Kirkland Signature, Trader Joe’s, and Sunkist labels, totaling approximately 13 million pounds. A total of 29 patients were affected by this outbreak, 7 of whom were hospitalized; no deaths were reported.
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Production – Peanut Butter
The origin of peanuts dates to around 950 BCE in South America. They were brought to Africa by early explorers, then transported to North America in the colonial age. Peanuts were first used as animal feed and human consumption began only in the late 19th century.
The four main varieties of commercially produced peanuts are runner, Virginia, Spanish, and Valencia. The U.S. production of peanuts is approximately 6.8 billion lbs. Georgia is the number one producer of peanuts, comprising almost half of U.S. production and value. In total, over one million acres of peanuts are planted and harvested in the U.S. each year. The average peanut farm is 200 acres. Approximately 60% of total production is dedicated for human consumption and the remaining is used for seed, animal feed, and oil. Over 60% of peanuts used for human consumption are processed into peanut butter.
Peanuts are typically planted in April or May and harvested in September and October, with a growing season lasting 140-150 days. Planting occurs after the last frost when soil temperatures are typically 65-70 degrees Fahrenheit. Peanut kernels are planted two inches deep and approximately one to two inches apart. Peanuts grow best in a loose, well-drained soil that have a slightly acidic pH of 6.0-6.5.
Since peanuts are formed underground, harvesting involves a machine digger pulling up the peanut plant to remove the plant from the soil. Days later after the moisture content of the plant has lowered, a shaker or picker will remove the plants from the field. The freshly harvested peanut pods are transferred into drying wagons to reduce the moisture content to 8-10% for storage.
Shelling removes the shell of the peanuts while minimizing damage to the kernel. Shelled peanuts are passed through a series of rollers that crack the peanut shell, then are pass over screens, destoners, and blowers to remove all shells and any foreign material. Once shelled, the peanuts are graded for size, color, and defects by the Agricultural Marketing Service. Following inspection and grading the peanuts can be transported to storage or shipped to manufacturers.
Peanut butter manufacturers will first dry roast the peanuts either in batches or through a continuous method directly before grinding. The continuous method of roasting is preferred by larger manufactures, where the peanuts are directly offloaded into an operation that roasts, cools, and grinds the peanuts into peanut butter. The batch method of roasting involves heating large batches of peanuts to 320 degrees Fahrenheit for 40-60 minutes. After batch roasting, the roasted peanuts are cooled to 86 degrees Fahrenheit and blanched. Blanched nuts are screened and inspected for scorched or undesirable nuts before grinding. Peanuts are mechanically grinded into butter by grinding mills consisting of two operations: first, the peanuts are ground into a medium grind, followed by a second grind into finer, smoother texture. For chunky varieties, peanut pieces may be added to smooth peanut butter following the grinding process or a rib can be removed from the grinder to allow for incomplete grinding. Once ground, the peanut butter is vacuum packaged into jars, capped, and labelled.
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One of the biggest concerns with nut butters, especially with peanut butter, is contamination with Salmonella because of this pathogen’s ability to survive in peanut butter despite the low water activity (aw). Researchers have found an initial inoculum of 5.68 log colony-forming units per gram (CFU/g) of peanut butter can result in greater than 3 log CFU/g after 1 week at 5 °C and 21 °C. Even after 24 weeks, approximately 2 and 1 log CFU/g Salmonella was detected at 5 °C and 21 °C, respectively. A 3-strain cocktail of Salmonella Tennessee inoculated in peanut butter survived for 2 weeks at 4 and 22 °C. Another pathogen, Listeria monocytogenes, was able to survive for 24 weeks in peanut butter at 20 °C with an initial inoculation level of 4 log CFU/g. Studies such as these suggest that pathogen contamination of peanut butter after heat processing could remain in the product throughout its shelf life. Potential contamination by L. monocytogenes prompted nationwide recalls of certain brands of peanut butter (2010) and peanut butter and jelly sandwiches (2011).
Better control technologies have been developed in response to outbreaks associated with peanuts. Adaptation of new processing techniques such as electron beam radiation to control pathogens in peanut butter has been studied. For example, a study examining high-pressure processing (HPP; 600 MPa for 5 min at 45 °C) against inoculated Salmonella in peanut butter found <2 log unit reductions. However, thermal treatment of peanut butter is not always effective since Salmonella has been shown to survive in peanut butter heated to 90 °C. This may be feasible due to the high fat content acting as a local buffer which allows Salmonella to survive with increased heat resistance. This finding suggests that peanut butter and other high fat and low aw foods cannot simply be heated to destroy all potential Salmonella pathogens. Furthermore, by utilizing the heat process too often, this may instead induce new stress responses in bacteria to adapt and thrive.
Together, the use of sanitary water, sanitary facilities, personal hygiene, plant sanitation, proper transportation, and other prevention-based food safety programs can help prevent any initial contamination to the product.
In 2020, the average American per capita peanut consumption rose to an all-time high of 7.6 lbs per year, driven in part by the an increased demand for peanut butter. Americans consume approximately 700 million pounds of peanut butter per year, spending almost $800 million a year on the product. Peanut butter and other nut butters have a wide range of uses; they are commonly consumed in sandwiches, snacks, candies, desserts, smoothies, and breakfast dishes. Nine out of ten American families consume peanut butter, in one form or another, by the time the average American child reaches adulthood. The average U.S. schoolchild today eats about 1,500 peanut butter and jelly sandwiches by the time high school graduation arrives.
The prevalence of peanut allergies in the United States tripled between 1997 and 2008, where more recent studies suggest that the prevalence has continued to rise 20% since 2010. To accommodate this allergen, the US seen a concurrent rise in the sale of other nut butters. This rising trend in peanut allergies has also led to the adoption of peanut-free policies in schools that advise school children to bring and consume peanut butter substitutes while at school.
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Nuts contain 70–80% fat, mostly unsaturated fatty acids (monounsaturated and polyunsaturated), which may be beneficial for glucose and insulin homeostasis. An ounce of plain nuts or two tablespoons of nut butter, without added salt or sugar, contains between 160 to 200 calories and about 13 to 20 grams of fat. However, nuts are naturally cholesterol free and low in saturated fat with only 1–2.5 grams per ounce. Nuts also supply important vitamins, such as vitamin E, folic acid, vitamin B-6, and niacin, and minerals such as magnesium, zinc, copper, and potassium. Different varieties of nut butter will slightly vary in nutritional value; for example, almond butter is highest in fiber and lowest in saturated fat, walnut butter is highest in omega-3 fatty acids, and cashew butter is lowest in protein. Epidemiological studies have suggested that nut and peanut butter consumption may reduce one’s risk of developing type 2 diabetes. Despite these benefits, nut butters should be consumed in moderation to avoid excessive calorie intake and weight gain.
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