Minimal Effects of High‐Pressure Treatment on Salmonella enterica Serovar Typhimurium Inoculated into Peanut Butter and Peanut Products

Abstract

About 1.2 billion pounds of peanut butter are consumed annually in the United States. In 2008 to 2009, an outbreak involving Salmonella Typhimurium in peanut butter led to a recall of over 3900 products by over 200 companies. More than 700 people became sick, 100 were hospitalized, and 9 people died from this outbreak. This study examines the efficacy of high-pressure processing (HPP) to decrease S. Typhimurium American Type Culture Collection (ATCC) 53647 inoculated into peanut butter and model systems. The viability of S. Typhimurium in peanut butter stored at room temperature was investigated. A culture of S. Typhimurium (6.88 log CFU/g) was inoculated into peanut butter. Following 28 d at 20 °C there was a 1.23-log reduction. Approximately 10(6) to 10(7) CFU/g S. Typhimurium were inoculated into 4 brands of peanut butter, 3 natural peanut butters and peanut flour slurries at 2, 5, and 10% peanut flour protein in peanut oil and in distilled water. All were treated at 600 MPa for 5 min at 45 °C. While significant differences were found between natural peanut butter and peanut protein mixtures, the reduction was <1.0 log. The peanut flour/oil mixtures had a 1.7, 1.6, and 1.0-log reduction from HPP (2, 5, and 10% protein, respectively) whereas peanut flour/water mixtures had a 6.7-log reduction for all protein levels. Oil had a protective effect indicating HPP may not help the microbial safety of water-in-oil food emulsions including peanut butter. Practical Application: There have been multiple outbreaks of foodborne illness involving peanut butter products. This study looks at the potential use of high-pressure processing to reduce the bacteria that may be in peanut butter.

Peanut and peanut products: A food safety perspective

“…These technologies need to be further examined for scale-up feasibility and efficacy. For example, a study examining high-pressure processing (HPP; 600 MPa for 5 min at 45 C) against inoculated Salmonella in peanut butter found only <2 log unit reductions (Grasso, Somerville, Balasubramaniam, & Lee, 2010). Since a 6.7 log unit reduction by HPP was achieved in a mixture of peanut flour and water, the fat content in oil could have provided protection for pathogens.…”

Plant based butters

“…In 2008 to 2009, an outbreak involving Salmonella Typhimurium in peanut butter led to a recall of over 3,900 products by over 200 companies. More than 700 people became sick, 100 were hospitalized, and 9 people died from this outbreak (Grasso et al 2010). Shachar and Yaron (2006) studied the heat tolerance of Salmonella enterica serovars Agona, Enteritidis, and Typhimurium in peanut butter and reported that the thermal treatments are inadequate to consistently destroy Salmonella in highly contaminated peanut butter and that the pasteurization process cannot be improved significantly by longer treatment or higher temperatures.…”

“…Similar results were also reported by Ma et al (2010), thermal treatments of peanut butter at 90°C for less than 30 min were not sufficient to kill large populations (5 log CFU/g) of Salmonella in highly contaminated peanut butter. Grasso et al (2010) examined the efficacy of high-pressure processing (HPP) to decrease S. Typhimurium American Type Culture Collection (ATCC) 53647 inoculated into peanut butter and model systems and reported that because of the protective effect of oil HPP may not help the microbial safety of water-in-oil food emulsions including peanut butter. Hvizdzak et al (2010) studied the effectiveness of electron beam (E-beam) radiation (0 to 3.1 kGy) for the reduction of Salmonella serovars Tennessee (ATCC 10722) and Typhimurium (ATCC 14028) in creamy peanut butter.…”

Inactivation of Salmonella Senftenberg, Salmonella Typhimurium and Salmonella Tennessee in peanut butter by 915 MHz microwave heating

“…Peanut butter, which usually contains over 90% peanuts with optional added sweeteners, salt and stabilizers (Grasso et al, 2010), constitutes the largest segment of peanut consumption. This is due to the increase in the consumption of peanut butter from 1999 to 2008 while peanut candy and snack consumption has not (USDA, 2010).…”