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Manhattan, KS, United States

Weber M.J.D.,Food Science Institute | Boyle E.A.E.,Kansas State University | Getty K.J.K.,Kansas State University | Harper N.M.,Kansas State University | And 2 more authors.
Journal of Food Protection | Year: 2011

Home-style dehydrators commonly used by consumers have limited relative humidity (RH) and temperature control. To evaluate the effect of dehydrator load on temperature and RH and subsequent reduction of Salmonella on whole-muscle chicken, chicken breasts were rolled and cut into samples (1 to 2 mm thick, 6 by 6 cm 2) and inoculated with a five-strain Salmonella cocktail. The samples were allowed to air dry for 15 min and then were loaded into home-style three-tray (3T) or five-tray (5T) dehydrators, with 12 chicken pieces per tray. No difference (P > 0.05) was observed in RH or temperature between the 3T and 5T dehydrators. Peak RH was 38% and gradually deceased to 8.5% after 6 h of drying. Temperatures peaked at 57uC after 6 h of drying. Dehydrator load had no effect (P > 0.05) on lethality for Salmonella. A reduction of 3.3 ± 0.2 log CFU/cm 2 was observed after 6 h of drying. However, sample location affected Salmonella reduction (P < 0.05). Samples from the bottom tray had a 1.5-log reduction, whereas samples from the top and middle trays had 4.1- and 3.9-log reductions, respectively. The water activity of samples after 6 h of drying was 0.71± 0.17 regardless of tray location or dehydrator type. When chicken was dried in home-style dehydrators, increasing the dehydrator load did not increase RH or achieve greater Salmonella lethality. Tray location had a significant impact on Salmonella lethality. Adequate reduction of Salmonella on chicken was not achieved when chamber temperatures were below 57°C with limited RH throughout drying. © International Association for Food Protection. Source

Yang S.,CAS South China Botanical Garden | Yang S.,University of Chinese Academy of Sciences | Chen Y.,CAS South China Botanical Garden | Chen Y.,University of Chinese Academy of Sciences | And 6 more authors.
Journal of Food Processing and Preservation | Year: 2011

The application of methyl jasmonate (MJ) for the control of pericarp browning of harvested lychees in relation to the levels of anthocyanins and (-)-epicatechin was investigated. Lychees were dipped for 3min in 0.6μg/L MJ+0.05% Sportak, 1μg/L MJ+0.05% Sportak, 5μg/L MJ+0.05% Sportak, 25μg/L MJ+0.05% Sportak or 0.05% Sportak (control). In this study, contents of anthocyanins (-)-epicatechin and lipofuscin-like substance, and browning index of harvested lychees during storage were determined. The activities of phenylalanine ammonia lyase (PAL), polyphenol oxidase and peroxidase were also measured. The treatment with MJ significantly maintained the contents of anthocyanins and (-)-epicatechin, delayed the accumulation of lipofuscin-like substance and extended the shelf life of lychees. Furthermore, MJ treatment increased PAL activity, which can account for the maintenance of anthocyanin or (-)-epicatechin content. After these treatments, 1μg/L MJ was effective in inhibiting pericarp browning and in maintaining the contents of anthocyanins and (-)-epicatechin of lychees. Thus, it is suggested that maintenance of anthocyanin or (-)-epicatechin contents could be an important factor for controlling pericarp browning of lychees during storage. © 2010 Wiley Periodicals, Inc. Source

Lobaton-Sulabo A.S.S.,Food Science Institute | Axman T.J.,Food Science Institute | Getty K.J.K.,Food Science Institute | Boyle E.A.E.,Food Science Institute | And 5 more authors.
Journal of Food Protection | Year: 2011

To validate how packaging and storage reduces Listeria monocytogenes on whole-muscle beef jerky and smoked pork and beef sausage sticks, four packaging systems (heat sealed [HS] without vacuum, heat sealed with oxygen scavenger, nitrogen flushed with oxygen scavenger [NFOS], and vacuum) and four ambient temperature storage times were evaluated. Commercially available whole-muscle beef jerky and smoked pork and beef sausage sticks were inoculated with a five-strain L. monocytogenes cocktail, packaged, and then stored at 25.5uC until enumerated for L. monocytogenes at 0, 24, 48, and 72 h and 30 days after packaging. The interaction of packaging and storage time affected L. monocytogenes reduction on jerky, but not on sausage sticks. A .2-log CFU/cm2 reduction was achieved on sausage sticks after 24 h of storage, regardless of package type, while jerky had ,2-log reductions for all packaging types. At 48 h, log reductions were similar (P . 0.05) for all types of jerky packaging, ranging from 1.26 to 1.72 log CFU/cm2; however, at 72 h, mean L. monocytogenes reductions were .2 log CFU/cm2, except for NFOS (1.22-log CFU/cm2 reduction). Processors could package beef jerky in HS packages with oxygen scavenger or vacuum in conjunction with a 24-h holding time as an antimicrobial process to ensure a .1-log CFU/cm2 L. monocytogenes reduction or use a 48-h holding time for HS-or NFOS-packaged beef jerky. A .3-log CFU/cm2 mean reduction was observed for all beef jerky and sausage stick packaging systems after 30 days of 25.5uC storage. © International Association for Food Protection. Source

Channaiah L.H.,AIB International | Holmgren E.S.,Food Science Institute | Michael M.,Food Science Institute | Sevart N.J.,Food Science Institute | And 7 more authors.
Journal of Food Protection | Year: 2016

This study was conducted to validate a simulated commercial baking process for hamburger buns to destroy Salmonella serovars and to determine the appropriateness of using nonpathogenic surrogates (Enterococcus faecium ATCC 8459 or Saccharomyces cerevisiae) for in-plant process validation studies. Wheat flour was inoculated (~6 log CFU/g) with three Salmonella serovars (Typhimurium, Newport, or Senftenberg 775W) or with E. faecium. Dough was formed, proofed, and baked to mimic commercial manufacturing conditions. Buns were baked for up to 13 min in a conventional oven (218.38C), with internal crumb temperature increasing to ~1008C during the first 8 min of baking and remaining at this temperature until removal from the oven. Salmonella and E. faecium populations were undetectable by enrichment (.6-log CFU/g reductions) after 9.0 and 11.5 min of baking, respectively, and -5-log-cycle reductions were achieved by 6.0 and 7.75 min, respectively. D-values of Salmonella (three-serovar cocktail) and E. faecium 8459 in dough were 28.64 and 133.33, 7.61 and 55.67, and 3.14 and 14.72 min at 55, 58, and 618C, respectively, whereas D-values of S. cerevisiae were 18.73, 5.67, and 1.03 min at 52, 55, and 588C, respectivly. The z-values of Salmonella, E. faecium, and S. cerevisiae were 6.58, 6.25, and 4.748C, respectively. A high level of thermal lethality was observed for baking of typical hamburger bun dough, resulting in rapid elimination of high levels of the three-strain Salmonella cocktail; however, the lethality and microbial destruction kinetics should not be extrapolated to other bakery products without further research. E. faecium demonstrated greater thermal resistance compared with Salmonella during bun baking and could serve as a conservative surrogate to validate thermal process lethality in commercial bun baking operations. Low thermal tolerance of S. cerevisiae relative to Salmonella serovars limits its usefulness as a surrogate for process validations. © Copyright International Association for Food Protection. Source

Lopez K.,Food Science Institute | Getty K.J.K.,Food Science Institute | Vahl C.I.,Kansas State University
Food Protection Trends | Year: 2015

Outbreaks associated with consumption of fresh produce have been linked to Escherichia coli 0157:H7 and Salmonella contamination. The objective was to determine the efficacy of a chemical wash treatment (citric acid, sodium lauryl sulfate, sodium carbonate, magnesium carbonate, and grapefruit oil extract) in reducing pathogens on the surface of leaf lettuce and tomatoes. Lettuce (25 ± 0.3 g) and whole tomatoes were inoculated with E. coli0157:H7 (∼7.8 log10 CFU/ml) and Salmonella spp. (9.39 log10 CFU/ml) cocktails, respectively. Samples were treated with cold tap water (negative control) or the chemical wash treatment for various exposure times (30, 60, and 120 s], and then rinsed with tap water. Samples then were plated on selective media. The chemical wash treatment was capable of reducing by ca. 3.0 log10 units of E. coli 0157:H7 and Salmonella spp. populations on the surface of leaf lettuce and tomatoes, respectively. Even though there were no significant differences among results with different exposure times [P < 0.05], application of the chemical wash treatment for 120 s lowered the mean populations of recovered pathogens by 0.1 to 0.66 log10 CFU. Therefore, it is recommended that the chemical wash treatment be applied for 120 s to obtain optimal log reductions on the surface of leaf lettuce and tomatoes. Source

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