A predictive growth model of Aeromonas hydrophila on chicken breasts under various storage temperatures

Scanning electron microscopy observation was used to investigate the ability of Aeromonas hydrophila to attach to various water distribution pipe surfaces, such as stainless Steel, copper, and polybutylene, after different contact times at ambient and storage temperatures. Surface energy value of each surface was estimated by contact angle measurements using water, α-bromonaphthalene, and dimethyl sulfoxide. Our results indicated that Aeromonas cells could easily attach to all surface types after exposures as short as 1 or 4 h at both temperatures (4 and 20°C). Polybutylene, a low-energy surface (41.2 mJ-m−2), followed by stainless Steel (65.7 mJ-m−2), was most colonized by Aeromonas cells, whereas few cells were observed on copper, which has a surface energy of 45.8 mJ-m−2. Extracellular materials could also be observed on polybutylene surfaces, especially after 1 and 4 h of exposure at the refrigeration temperature.

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Growth Model of Escherichia coli O157:H7 at Various Storage Temperatures on Kale Treated by Thermosonication Combined with Slightly Acidic Electrolyzed Water

Journal of Food Protection ◽

10.4315/0362-028x.jfp-13-283 ◽

2014 ◽

Vol 77 (1) ◽

pp. 23-31 ◽

Cited By ~ 10

Author(s):

AHMAD ROIS MANSUR ◽

JUN WANG ◽

MYEONG-SU PARK ◽

DEOG-HWAN OH

Keyword(s):

Escherichia Coli ◽

Growth Model ◽

Storage Temperature ◽

Growth Parameters ◽

Model Development ◽

Escherichia Coli O157 ◽

Electrolyzed Water ◽

E Coli ◽

Significant Difference ◽

Storage Temperatures

This study was conducted to investigate the disinfection efficacy of hurdle treatments (thermosonication plus slightly acidic electrolyzed water [SAcEW]) and to develop a model for describing the effect of storage temperatures (4, 10, 15, 20, 25, 30, and 35°C) on the growth of Escherichia coli O157:H7 on fresh-cut kale treated with or without (control) thermosonication combined with SAcEW. The hurdle treatments of thermosonication plus SAcEW had strong bactericidal effects against E. coli O157:H7 on kale, with approximately 3.3-log reductions. A modified Gompertz model was used to describe growth parameters such as specific growth rate (SGR) and lag time (LT) as a function of storage temperature, with high coefficients of determination (R2 > 0.98). SGR increased and LT declined with rising temperatures in all samples. A significant difference was found between the SGR values obtained from treated and untreated samples. Secondary models were established for SGR and LT to evaluate the effects of storage temperature on the growth kinetics of E. coli O157:H7 in treated and untreated kale. Statistical evaluation was carried out to validate the performance of the developed models, based on the additional experimental data not used for the model development. The validation step indicated that the overall predictions were inside the acceptable prediction zone and had lower standard errors, indicating that this new growth model can be used to assess the risk of E. coli O157:H7 contamination on kale.

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