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Ramsay EW, Bardsley C, Desiree K, Rubinelli P, Fernandes S, Acuff JC. The Use of Antimicrobial Washes to Inactivate Shiga Toxin-Producing Escherichia coli from In-Shell Pecans and Wash Water Contaminated by Different Inoculation Routes. J Food Prot 2024; 87:100332. [PMID: 39029800 DOI: 10.1016/j.jfp.2024.100332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 07/12/2024] [Accepted: 07/14/2024] [Indexed: 07/21/2024]
Abstract
In-shell pecans are typically harvested after falling from trees to the ground, presenting a potential route of contamination of foodborne pathogens from soil contact. In-shell pecans are often subjected to various processing or washing steps prior to being shelled. This study determined Shiga toxin-producing Escherichia coli (STEC) reductions after treatment with antimicrobial washes on direct and soil-inoculated in-shell pecans and evaluated the cross-contamination potential of the spent pecan washes after treatment. Pecans were directly and soil-inoculated with an STEC cocktail (O157:H7, O157:NM, O121, O26). Direct inoculation was achieved by spraying the STEC cocktail on the pecans. For soil-inoculation pecans, autoclaved soil was sprayed with the STEC cocktail, homogenized for 2 min, and used to coat in-shell pecans. Inoculated pecans were washed in treatments of 2% lactic acid (LA), 1,000 ppm free chlorine (sodium hypochlorite; NaClO), hot water (HW; 85 ± 2 °C), or ambient water (C [control]; 18 ± 2 °C) for 2, 5, and 10 min and diluted to enumerate STEC populations. After treatments, 100 mL of the spent wash was vacuum filtered through a 0.45-µm membrane and plated on selective agar. HW significantly reduced STEC populations from pecans with and without soil regardless of treatment time (p < 0.05), NaClO reduced STEC populations more than the ambient control wash on directly inoculated pecans, but there were no significant differences between STEC reductions from ambient water (C), LA, and NaClO treatments on soil-inoculated pecans (p > 0.05). Larger STEC populations were enumerated from ambient water wash compared to the antimicrobial washes (p < 0.05). The HW, LA, and NaClO treatments were effective at maintaining the quality of the wash water, with STEC levels being generally at or below the detection limit (<1 CFU/100 mL), while HW was the most effective at reducing STEC from in-shell pecans with and without a soil coating (>5-log CFU/mL reductions).
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Affiliation(s)
- Erin W Ramsay
- Department of Food Science, University of Arkansas System Division of Agriculture, 2650 N Young Ave., Fayetteville, AR 72704, USA
| | - Cameron Bardsley
- USDA ARS Fruit and Tree Nut Research Unit, 21 Dunbar Rd., Byron, GA 31008, USA
| | - Karina Desiree
- Department of Food Science, University of Arkansas System Division of Agriculture, 2650 N Young Ave., Fayetteville, AR 72704, USA
| | - Peter Rubinelli
- Department of Food Science, University of Arkansas System Division of Agriculture, 2650 N Young Ave., Fayetteville, AR 72704, USA
| | - Samuel Fernandes
- Center For Agricultural Data Analytics, University of Arkansas System Division of Agriculture, 935 W Maple St., Fayetteville, AR 72701, USA
| | - Jennifer C Acuff
- Department of Food Science, University of Arkansas System Division of Agriculture, 2650 N Young Ave., Fayetteville, AR 72704, USA.
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Liu Z, Liao C, Golson K, Phillips S, Wang L. Survival of common foodborne pathogens on dried apricots made with and without sulfur dioxide treatment. Food Control 2021. [DOI: 10.1016/j.foodcont.2020.107569] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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3
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Ozone-based treatments for inactivation of Salmonella enterica in tree nuts: Inoculation protocol and surrogate suitability considerations. Int J Food Microbiol 2019; 297:21-26. [PMID: 30856385 DOI: 10.1016/j.ijfoodmicro.2019.02.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 01/24/2019] [Accepted: 02/28/2019] [Indexed: 11/23/2022]
Abstract
The feasibility of using gaseous ozone, alone or in combination with other treatments, to decontaminate in-shell almonds and pistachios, prepared under different pathogen-inoculation conditions, was explored. Nuts were inoculated with either Salmonella enterica serovar Enteritidis or a potential Salmonella surrogate, Enterococcus faecium OSY 31284. The effect of inoculation method (with or without vacuum application), and of drying inoculated nuts (up to three days) on treatment efficacy was investigated. Inoculated nuts were subjected to gaseous ozone alone (almonds, pistachios) or ozone in combination with heating in brine solution (pistachios). Ozone treatment included application of vacuum (10 in Hg), followed by vessel pressurization to 12.5 psig with ozone‑oxygen mixture (160 g ozone/m3 gas mixture) and holding for 30 min. Heating was conducted in a brine solution (5% NaCl) at 70 °C, for 10 min. Ozone-based treatments were significantly more effective (P < 0.05) on almonds than pistachios, with maximum S. Enteritidis reduction of 2.9 vs. 0.8 log CFU/g, regardless of inoculation method or the drying time. Treatment of inoculated pistachios with heated brine and gaseous ozone reduced S. Enteritidis population by 5.0 to 7.0 log CFU/g and was not significantly more effective than treatment with heated brine alone (reduction of 4.8 to 7.1 log CFU/g). Application of vacuum during inoculation increased bacterial population on nut kernels by approximately 1.2 log CFU/g, but the increase in inoculum population had no effect on inactivation of either species of inoculated bacteria. Decontamination treatments were less effective against both bacteria by up to 2 log CFU/g when drying time of inoculated nuts increased. E. faecium was significantly more resistant to heat and ozone treatment (P < 0.05) than was S. Enteritidis on pistachios, but not on almonds. Results of this study show that laboratory methodology affects observed treatment effectiveness. Considering its high resistance to the heat-ozone combination, E. faecium may not be a suitable surrogate for S. Enteritidis during processing of pistachios by this treatment. Efficacy of ozone gas to decontaminate S. Enteritidis-inoculated nuts depends heavily on the type of nut. Although reductions of S. Enteritidis populations on in-shell pistachios are low, treatment of in-shell almonds resulted in greater reductions, indicating the promise of this technology to enhance the safety of specific nut products.
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Kharel K, Prinyawiwatkul W, Yemmireddy VK, Graham CJ, Adhikari A. Effect of hot water treatment of in‐shell pecans on physicochemical properties and consumer acceptability of roasted pecan kernels. Int J Food Sci Technol 2019. [DOI: 10.1111/ijfs.14096] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Karuna Kharel
- School of Nutrition and Food Sciences Louisiana State University Agricultural Center Baton Rouge LA 70803‐4200 USA
| | - Witoon Prinyawiwatkul
- School of Nutrition and Food Sciences Louisiana State University Agricultural Center Baton Rouge LA 70803‐4200 USA
| | - Veerachandra K. Yemmireddy
- School of Nutrition and Food Sciences Louisiana State University Agricultural Center Baton Rouge LA 70803‐4200 USA
- School of Earth, Environmental and Marine Sciences University of Texas Rio Grande Valley Edinburg TX 78539‐2909 USA
| | - Charles J. Graham
- Red River Research Station Louisiana State University Agricultural Center Bossier City LA 71112 USA
| | - Achyut Adhikari
- School of Nutrition and Food Sciences Louisiana State University Agricultural Center Baton Rouge LA 70803‐4200 USA
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Brar PK, Danyluk MD. Validation of Enterococcus faecium as a surrogate for Salmonella under different processing conditions for peanuts and pecans. Food Microbiol 2018; 80:9-17. [PMID: 30704601 DOI: 10.1016/j.fm.2018.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/03/2018] [Accepted: 12/05/2018] [Indexed: 11/18/2022]
Abstract
Food Safety and Modernization Act (FSMA) Preventive Control rules require nut processors validate thermal processes to ensure a desirable log reduction of Salmonella is achieved. Due to the complex nature of nut and nut products, processes and equipment, it is difficult to use one validation study for all and may requires individual equipment be validated at the plant level. In plant validation studies, pathogens such as Salmonella cannot be used due to the risk of contamination, thus the suitability of a non-pathogenic organism, Enterococcus faecium as a surrogate for Salmonella was evaluated for peanut and pecan thermal processing. Stagnant and forced dry air heating conditions, (120 °C (20, 30, 40 min), 130 °C (10, 20, 30 min), 140 °C (10, 20, 30 min)) were evaluated for unblanched peanut kernels. Oil heating conditions (116 °C, 121 °C, and 127 °C for 0.5, 1.0, 1.5, 2.0, 2.5 min) were evaluated for pecan kernels. Inshell pecans are conditioned in hot or cold water to facilitate the shelling process. Water heating conditions (75 °C (20, 40, 80, 120 s), 80 °C (20, 40, 80, 120 s), 85 °C (20, 40, 80, 120 s), 90 °C (20, 40, 60, 80 s), and 95 °C (20, 40, 60, 80 s)) were evaluated for inshell pecans. Under conditions, except forced air treatment, E. faecium reductions (Log N/N0) were either not significantly different (P > 0.05) or significantly lower than Salmonella (P < 0.05), making it a suitable surrogate for the processes evaluated.
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Affiliation(s)
- Pardeepinder K Brar
- Department of Food Science and Human Nutrition, Citrus Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred, FL, 33850, USA
| | - M D Danyluk
- Department of Food Science and Human Nutrition, Citrus Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred, FL, 33850, USA.
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Kharel K, Yemmireddy VK, Graham CJ, Prinyawiwatkul W, Adhikari A. Hot water treatment as a kill-step to inactivate Escherichia coli O157:H7, Salmonella enterica, Listeria monocytogenes and Enterococcus faecium on in-shell pecans. Lebensm Wiss Technol 2018. [DOI: 10.1016/j.lwt.2018.07.048] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Brar PK, Danyluk MD. Nuts and Grains: Microbiology and Preharvest Contamination Risks. Microbiol Spectr 2018; 6:10.1128/microbiolspec.pfs-0023-2018. [PMID: 29701166 PMCID: PMC11633566 DOI: 10.1128/microbiolspec.pfs-0023-2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Indexed: 11/20/2022] Open
Abstract
Low-water-activity foods have been involved in recalls and foodborne disease outbreaks. Increased consumption; better detection methods and reporting systems; improved surveillance, trace-back, and ability to connect sporadic foodborne illnesses; and inadequate implementation of food safety programs are some of the likely reasons for the increase in frequency of recalls and outbreaks linked to dry foods. Nuts and grains can be contaminated with foodborne pathogens at any stage during production, processing, storage, and distribution. Focusing on preharvest contamination, the various potential sources of contamination include soil, animal intrusion, contaminated harvesting equipment, harvest and preharvest handling, storage conditions, and others. The low water activity of nuts and grains prevents the growth of most foodborne pathogens on their surfaces. The long-term survival of bacterial foodborne pathogens (Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes) on dry foods has been documented in the literature for different nut types. Preventing contamination is the key to avoiding foodborne disease risks linked to dry foods. The implementation of good agricultural practices and other food safety systems provides a proactive approach to address concerns thoroughly. A plethora of research is available on preventing the growth of mycotoxin-producing fungi on the surface of nuts and grains. Milling is an effective mechanism to reduce the microbial load on grains. This review focuses on providing information about associated foodborne microorganisms, preharvest contamination sources, and good agricultural practice recommendations for nuts and grains.
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Affiliation(s)
- Pardeepinder K Brar
- Department of Food Science and Human Nutrition, Citrus Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850
| | - Michelle D Danyluk
- Department of Food Science and Human Nutrition, Citrus Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL 33850
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Dry-inoculation method for thermal inactivation studies in wheat flour using freeze-dried Enterococcus faecium NRRL B-2354. Lebensm Wiss Technol 2018. [DOI: 10.1016/j.lwt.2017.10.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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9
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Farakos SMS, Pouillot R, Johnson R, Spungen J, Son I, Anderson N, Davidson GR, Doren JMV. A Quantitative Assessment of the Risk of Human Salmonellosis Arising from the Consumption of Pecans in the United States. J Food Prot 2017; 80:1574-1591. [PMID: 28812908 DOI: 10.4315/0362-028x.jfp-16-511] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A quantitative risk assessment was conducted to assess the risk of human salmonellosis acquired from consumption of pecans in the United States. The model considered the potential for Salmonella survival, growth, and recontamination of pecans from the sheller to the consumer, including steps such as immersion in water, drying, conditioning, cracking, partitioning, and storage. Five theoretical microbial reduction treatment levels (1 to 5 log CFU) were modeled. Data from the 2010 to 2013 surveys by the National Pecan Shellers Association were used for initial prevalence and contamination levels. The impacts of atypical situations in the pecan production system were also evaluated. Higher initial contamination levels, recontamination during processing, and a delay in drying postconditioning were the modeled atypical situations. The baseline model predicted a mean risk of salmonellosis in the United States from consumption of in-shell and shelled pecans processed by cold conditioning with no microbial reduction treatment and no further home cooking as 1 case per 775,193 servings (95% confidence interval [CI]: 1 case per 1,915,709 to 178,253 servings). This predicted risk per serving was estimated as a mean of 529 cases of salmonellosis per year (95% CI: 213 to 2,295 cases). Hot conditioning for shelled pecans and microbial reduction treatment of both shelled and in-shell pecans had a significant impact on the predicted mean risk of illness. Assuming 77% of the shelled pecans sold at retail (i.e., 80% of the retail supply) received hot conditioning, the mean estimated salmonellosis cases per year from consumption of in-shell and shelled pecans uncooked at home was 203 (95% CI: 81 to 882 cases) if no additional microbial reduction treatment were applied. The predicted risk of illness per serving was higher for all atypical situations modeled compared with the baseline model, and delay in drying had the greatest impact on risk.
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Affiliation(s)
- Sofia M Santillana Farakos
- 1 U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, Maryland 20740 (ORCID: http://orcid.org/0000-0002-6107-5212 [R.P.]); and
| | - Régis Pouillot
- 1 U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, Maryland 20740 (ORCID: http://orcid.org/0000-0002-6107-5212 [R.P.]); and
| | - Rhoma Johnson
- 1 U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, Maryland 20740 (ORCID: http://orcid.org/0000-0002-6107-5212 [R.P.]); and
| | - Judith Spungen
- 1 U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, Maryland 20740 (ORCID: http://orcid.org/0000-0002-6107-5212 [R.P.]); and
| | - Insook Son
- 1 U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, Maryland 20740 (ORCID: http://orcid.org/0000-0002-6107-5212 [R.P.]); and
| | - Nathan Anderson
- 2 U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Bedford Park, Illinois 60501, USA
| | - Gordon R Davidson
- 1 U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, Maryland 20740 (ORCID: http://orcid.org/0000-0002-6107-5212 [R.P.]); and
| | - Jane M Van Doren
- 1 U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, Maryland 20740 (ORCID: http://orcid.org/0000-0002-6107-5212 [R.P.]); and
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Brar PK, Strawn LK, Danyluk MD. Prevalence, Level, and Types of Salmonella Isolated from North American In-Shell Pecans over Four Harvest Years. J Food Prot 2016; 79:352-60. [PMID: 26939644 DOI: 10.4315/0362-028x.jfp-15-365] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In-shell pecan samples (500 g) were collected over four harvest seasons (2010 to 2014) from seven pecan shelling facilities located in five U.S. states. Four varieties of pecans were analyzed: Mexican Improved, Native Seedlings, Southern Improved, and Western Improved. Pecan samples (100 g) were sent to a third party laboratory for initial Salmonella screening. When a sample was positive for Salmonella, the pathogen level was determined by the most-probable-number (MPN) method (25, 2.5, and 0.25 g). Two sample preparation strategies were used for the MPN analysis, and both strategies were combined for the reported MPN values. Forty-four (0.95%) of 4,641 in-shell pecan samples were positive for Salmonella during initial screening; prevalence by year was 0.47 to 1.4%. Prevalence was not significantly different between varieties: Mexican Improved, 1.2%; Native/Seedling, 0.99%; Southern Improved, 0.97%; and Western Improved, 0.75%. Salmonella was not isolated from 31 of 44 samples upon retesting during MPN analysis (<0.47 MPN/100 g). When Salmonella was detected, the levels were 0.47 to 39 MPN/100 g, with a mean of 2.4 MPN/100 g. Thirty-one Salmonella serotypes were obtained from 42 Salmonella-positive pecan samples; Enteritidis was the most common (12% of samples) followed by Javiana (9%) and Braenderup (7%). All Salmonella Enteritidis isolates were phage type 8. Pulsed-field gel electrophoresis analysis (XbaI) revealed within-serotype diversity, indicating introduction of contamination from a variety of sources. Most (64%) of the isolates were resistant to streptomycin or tetracycline, and 13% were resistant to three or more antibiotics. Salmonella prevalence and level on in-shell pecans is comparable to that on other nuts.
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Affiliation(s)
- Pardeepinder K Brar
- Department of Food Science and Human Nutrition, Citrus Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred, Florida 33850, USA
| | - Laura K Strawn
- Department of Food Science and Technology, Agricultural Research and Extension Center, Virginia Polytechnic Institute and State University, 33446 Research Drive, Painter, Virginia 23420, USA
| | - Michelle D Danyluk
- Department of Food Science and Human Nutrition, Citrus Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred, Florida 33850,
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Smith AL, Perry JJ, Marshall JA, Yousef AE, Barringer SA. Oven, Microwave, and Combination Roasting of Peanuts: Comparison of Inactivation ofSalmonellaSurrogateEnterococcus faecium, Color, Volatiles, Flavor, and Lipid Oxidation. J Food Sci 2014; 79:S1584-94. [DOI: 10.1111/1750-3841.12528] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 05/02/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Alicia L. Smith
- Dept. of Food Science and Technology; The Ohio State Univ; 110 Parker Food Science Building, 2015 Fyffe Rd. Columbus OH 43210 U.S.A
| | - Jennifer J. Perry
- Dept. of Food Science and Technology; The Ohio State Univ; 110 Parker Food Science Building, 2015 Fyffe Rd. Columbus OH 43210 U.S.A
| | | | - Ahmed E. Yousef
- Dept. of Food Science and Technology; The Ohio State Univ; 110 Parker Food Science Building, 2015 Fyffe Rd. Columbus OH 43210 U.S.A
| | - Sheryl A. Barringer
- Dept. of Food Science and Technology; The Ohio State Univ; 110 Parker Food Science Building, 2015 Fyffe Rd. Columbus OH 43210 U.S.A
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Radiation D10 values for Salmonella Typhimurium LT2 and an Escherichia coli cocktail in pecan nuts (Kanza cultivar) exposed to different atmospheres. Food Control 2014. [DOI: 10.1016/j.foodcont.2013.10.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Beuchat LR, Mann DA, Alali WQ. Efficacy of sanitizers in reducing Salmonella on pecan nutmeats during cracking and shelling. J Food Prot 2013; 76:770-8. [PMID: 23643118 DOI: 10.4315/0362-028x.jfp-12-541] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Studies were done to evaluate the efficacy of chlorine (200 to 1,000 μg/ml), lactic acid (0.5 to 2%), levulinic acid (0.5 to 2%), sodium dodecyl sulfate (SDS, 0.05%), lactic acid plus SDS, levulinic acid plus SDS, and a mixed peroxyacid sanitizer (Tsunami 200, 40 and 80 μg/ml) in killing Salmonella on or in immersion- and on surface-inoculated pecan nutmeats (U.S. Department of Agriculture medium pieces and mammoth halves). The addition of SDS to treatment solutions containing lactic acid or levulinic acid resulted in generally higher reductions of Salmonella, but differences in these reductions were not always significant. Lactic and levulinic acids (2%) containing SDS (0.05%) were equivalent in killing Salmonella on immersion-inoculated nutmeats. Tsunami 200 (40 μg/ml) was less lethal or equivalent to 1 or 2% lactic and levulinic acids, with or without 0.05% SDS. Reductions did not exceed 1.1 log CFU/g of immersion-inoculated pieces and halves, regardless of sanitizer concentration or treatment time (up to 20 min). Reductions on surface-inoculated pieces and halves were 0.7 to 2.6 log CFU/g and 1.2 to 3.0 log CFU/g, respectively. Treatment with 2% lactic acid plus SDS (0.05%) and Tsunami (80 μg/ml) was most effective in killing Salmonella on surface-inoculated pieces; treatment of halves with chlorine (1,000 μg/ml) or lactic acid (1 or 2%), with or without SDS, was most efficacious. Exposure of immersion-inoculated pecan pieces to chlorine (200 μg/ml), lactic acid (2%) and levulinic acid (2%) with or without SDS, and Tsunami (80 μg/ml) during intermittent vacuum (18 ± 2 mbar) and ambient atmospheric pressure treatments for up to 20 min reduced Salmonella by only 0.1 to 1.0 log CFU/g. These studies emphasize the importance of preventing contamination of pecan nutmeats with Salmonella. Once nuts are contaminated, the lethality of sanitizers tested in this study is minimal.
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Affiliation(s)
- Larry R Beuchat
- Center for Food Safety and Department of Food Science and Technology University of Georgia, 1109 Experiment Street, Griffin, Georgia 30223-1797, USA.
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Beuchat LR, Mann DA, Alali WQ. Evaluation of sanitizers for inactivating Salmonella on in-shell pecans and pecan nutmeats. J Food Prot 2012; 75:1930-8. [PMID: 23127701 DOI: 10.4315/0362-028x.jfp-12-133] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Chlorine, organic acids, and water extracts of inedible pecan components were tested for effectiveness in killing Salmonella on pecans. In-shell pecans and nutmeats (U.S. Department of Agriculture medium pieces) were immersion inoculated with a mixture of five Salmonella serotypes, dried to 3.7% moisture, and stored at 4°C for 3 to 6 weeks. In-shell nuts were immersed in chlorinated water (200, 400, and 1,000 μg/ml), lactic acid (0.5, 1, and 2%), and levulinic acid (0.5, 1, and 2%) with and without 0.05% sodium dodecyl sulfate (SDS), and a mixed peroxyacid sanitizer (Tsunami 200, 40 μg/ml) for up to 20 min at 21°C. The rate of reduction of free chlorine in conditioning water decreased as the ratio of in-shell nuts/water was increased. The rate of reduction was more rapid when nuts were not precleaned before treatment. The initial population of Salmonella on in-shell nuts (5.9 to 6.3 log CFU/g) was reduced by 2.8 log CFU/g after treating with chlorinated water (1,000 μg/ml). Treatment with 2% lactic acid plus SDS or 2% levulinic acid plus SDS reduced the pathogen by 3.7 and 3.4 log CFU/g, respectively. Lactic and levulinic acids (2%) without SDS were less effective (3.3- and 2.1-log CFU/g reductions, respectively) than acids with SDS. Treatment with Tsunami 200 resulted in a 2.4-log CFU/g reduction. In-shell nuts and nutmeats were immersed in water extracts of ground pecan shucks (hulls), shells, a mixture of shells and pith, and pith. The general order of lethality of extracts to Salmonella was shuck < shell-pith ≤ shell ≤ pith < chlorine (400 μg/ml) and shuck < shell ≤ pith = shell-pith < chlorine (400 μg/ml). Results emphasize the importance of removing soil and dust on in-shell pecans before conditioning in chlorinated water and the need for sanitizers with increased effectiveness in killing Salmonella on pecans.
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Affiliation(s)
- Larry R Beuchat
- Department of Food Science and Technology, University of Georgia, Griffin, GA 30223-1797, USA.
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Beuchat LR, Mann DA. Inactivation of Salmonella on pecan nutmeats by hot air treatment and oil roasting. J Food Prot 2011; 74:1441-50. [PMID: 21902912 DOI: 10.4315/0362-028x.jfp-11-080] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Studies were done to determine the effectiveness of hot air drying, dry roasting, and oil roasting in killing Salmonella on pecan nutmeats. Pecan halves and pieces were inoculated by immersion in a five-serotype suspension of Salmonella or by surface application of powdered chalk containing the pathogen. Hot air treatment of low-moisture (2.8 to 4.1%) and high-moisture (10.5 to 11.2%) immersion-inoculated nutmeats (initial population, 6.18 to 7.16 log CFU/g) at 120°C for 20 min reduced the number of Salmonella by 1.18 to 1.26 and 1.89 to 2.04 log CFU/g, respectively. However, regardless of the moisture content, hot air treatment of pecan halves containing 0.77 log CFU/g at 120°C for 20 min failed to eliminate Salmonella. Reductions were >7 log CFU/g when dry pieces were dry roasted at 160°C for 15 min. Treatment of halves at 140°C for 20 min, 150°C for 15 min, or 170°C for 10 min reduced Salmonella by 5 log CFU/g. The pathogen was slightly more heat resistant in immersion-inoculated nutmeats than on surface-inoculated nutmeats. Exposure of immersion-inoculated pieces to peanut oil at 127°C for 1.5 min or 132°C for 1.0 min reduced the number of Salmonella by 5 log CFU/g. Treatment of halves at 138°C for 2.0 min reduced Salmonella by 5 log CFU/g; treatment at 132°C for 2.5 to 4.0 min did not always achieve this reduction. Hot air treatment cannot be relied upon to reduce Salmonella by 5 log CFU/g of raw pecan nutmeats without changing sensory qualities. Treatment temperatures and times typically used to oil roast nutmeats appear to be sufficient to reduce Salmonella by 5 log CFU/g.
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Affiliation(s)
- Larry R Beuchat
- Center for Food Safety and Department of Food Science and Technology, University of Georgia, 1109 Experiment Street, Griffin, Georgia 30223-1797, USA.
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