Effectiveness of Sanitizers, Dry Heat, Hot Water, and Gas Catalytic Infrared Heat Treatments to Inactivate Salmonella on Almonds

Abstract

The majority of almond-related foodborne outbreaks have been associated with Salmonella. Therefore, it is necessary to find an effective method to inactivate these organisms on raw almond prior to market distribution. This study was conducted to assess the effectiveness of sanitizers (strong or mild electrolyzed water, ozonated water, and distilled water), dry heat treatment, and hot water treatments followed by catalytic infrared (IR) heat treatment to inactivate Salmonella populations on raw almond. Raw almonds inoculated with four-strain cocktails of Salmonella were treated either by soaking in different chemical sanitizers or with dry heat and/or hot water for various periods of time followed by catalytic IR heat treatment for 70 seconds. The treated seeds were then assessed for the efficacy of the treatment in reducing populations of the pathogens. After inoculation and air-drying, 5.73 +/- 0.12 log colony-forming units (CFU)/g Salmonella were detected in nonselective medium. Sanitizer treatment alone did not show significant reduction in the Salmonella population, but in combination with IR drying it reduced the population to 3.0 log CFU/g. Dry heating at 60 degrees C for 4 days followed by IR drying for 70 seconds reduced the Salmonella population an additional 1.0 log CFU/g. Hot water treatments at 85 degrees C for 40 seconds followed by IR drying for 70 seconds reduced pathogens to an undetectable level by direct plating, but not by enrichment.

Effect of moisture on salmonella spp. heat resistance in cocoa and hazelnut shells

“…Heating of raw almonds by steam (Lee et al, 2006), dry heat, superheated steam, hot water or infrared (IR) heating (Bari et al, 2010(Bari et al, , 2009, clearly showed that moist heat was the most efficacious of the heating régimes. However, moisture added to almonds by steam or hot water treatments, must be removed (e.g.…”

“…Goepfert and Biggie (1968) demonstrated the high heat resistance of salmonellae in cocoa liquor, while showed that heat resistance could be substantially lowered in this matrix, by addition of small amounts of water (1-4% w/w). Whilst data is available on the effectiveness of heat treatments and heat resistance of salmonellae in almonds (Bari et al, 2010(Bari et al, , 2009Chang, Han, Reyes-De-Corcuera, Powers, & Kang, 2010;Du, Abd, McCarthy, & Harris, 2010), pecan nutmeats (Beuchat & Mann, 2011) and other low a W foods, such as peanut butter (Ma et al, 2009;Shachar & Yaron, 2006), no similar data in other low a W confectionery raw materials is currently in the public domain. This study addresses the apparent lack of such data by determining the heat resistance of several strains of Salmonella in crushed shells of cocoa and hazelnut at low and elevated water content.…”

Survival of Salmonella Enteritidis PT 30 on inoculated almond kernels in hot water treatments

“…Since September 2007, in response to these outbreaks, almonds grown in California and sold in North America (U.S., Canada and Mexico) must be processed to achieve a minimum 4-log reduction of Salmonella using a validated process (Federal Register 2007). These processes may either induce desirable sensory characteristics (e.g., roasting or blanching) (Du, Abd, McCarthy, & Harris 2010) or may be designed to retain attributes of the raw almond (e.g., propylene oxide, high pressure, infrared heating, moist air impingement, steam or combination treatments) (ABC, 2007a;Bari et al 2009; Bari et al 2010;Brandl, Pan, Huynh, Zhu, & McHugh 2008;Chang, Han, Reyes-De-Corcuera, Powers, & Kang 2010;Jeong, Marks, & Orta-Ramirez 2009;Lee et al 2006;Willford, Mendonca, & Goodridge 2008;Yang et al 2010).…”

Inactivation of Salmonella on In-Shell Pecans during Conditioning Treatments Preceding Cracking and Shelling

“…Results from studies on thermal tolerance characteristics of Salmonella on almond kernels were used to develop guidelines for process validation (1). Several studies describing inactivation of Salmonella on almond kernels upon treatment with dry heat (2,21), moist heat (19), steam (24), hot water (2,39), infrared heat (2,6), hot oil (13), and propylene oxide (12) have been published.…”

“…Reductions in Salmonella on Nonpareil almond kernels resulting from hot water treatment at 70, 80, and 88uC have been reported to be 1.7, 3.0, and 4.6 log CFU/g, respectively, within 30 s (39). Treatment of almonds in water at 85 and 88uC for 40 and 20 s, respectively, reduced Salmonella by at least 5.73 log CFU/g (2). Salmonella in peanut butter also is known to have a high tolerance to heat.…”