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Survival of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes on inoculated almonds and pistachios stored at -19, 4, and 24° C.
- Source :
-
Journal of food protection [J Food Prot] 2012 Aug; Vol. 75 (8), pp. 1394-403. - Publication Year :
- 2012
-
Abstract
- The survival of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes was determined on almonds and pistachios held at typical storage temperatures. Almond kernels and inshell pistachios were inoculated with four- to six-strain cocktails of nalidixic acid-resistant Salmonella, E. coli O157:H7, or L. monocytogenes at 6 log CFU/g and then dried for 72 h. After drying, inoculated nuts were stored at -19, 4, or 24°C for up to 12 months. During the initial drying period after inoculation, levels of all pathogens declined by 1 to -log CFU/g on both almonds and pistachios. During storage, moisture content (4.8%) and water activity (0.4) of the almonds and pistachios were consistent at -19°C; increased slowly to 6% and 0.6, respectively, at 4°C; and fluctuated from 4 to 5% and 0.3 to 0.5 at 24°C, respectively. Every 1 or 2 months, levels of each pathogen were enumerated by plating; samples were enriched when levels fell below the limit of detection. No reduction in population level was observed at -19 or 4°C for either pathogen, with the exception of E. coli O157:H7-inoculated almonds stored at 4°C (decline of 0.09 log CFU/g/month). At 24°C, initial rates of decline were 0.20, 0.60, and 0.71 log CFU/g/month on almonds and 0.15, 0.35, and 0.86 log CFU/g/month on pistachios for Salmonella, E. coli O157:H7, and L. monocytogenes, respectively, but distinct tailing of the survival curves was noted for both E. coli O157:H7 and L. monocytogenes.
- Subjects :
- Colony Count, Microbial
Food Handling
Food Microbiology
Microbial Viability
Temperature
Time Factors
Water metabolism
Escherichia coli O157 growth & development
Food Preservation methods
Listeria monocytogenes growth & development
Pistacia microbiology
Prunus microbiology
Salmonella growth & development
Subjects
Details
- Language :
- English
- ISSN :
- 1944-9097
- Volume :
- 75
- Issue :
- 8
- Database :
- MEDLINE
- Journal :
- Journal of food protection
- Publication Type :
- Academic Journal
- Accession number :
- 22856562
- Full Text :
- https://doi.org/10.4315/0362-028X.JFP-12-023