Survivability of Escherichia coli O157:H7 ATCC 43888 and Enterococcus faecium ATCC 8459 in a Hydrocolloid Gel Bar Model and Macronutrient Bar Model in Response to Vacuum Microwave Drying and Storage

This study aimed to investigate the microbial safety of Vacuum Microwave Drying (VMD) and 30 days storage at 25 °C on survivability of Escherichia coli O157:H7 ATCC 43888 and Enterococcus faecium ATCC 8459 in a nutritionally minimal bar model and macronutrient bar model. Sodium alginate hydrocolloid...

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Main Authors: Dominique Pacitto-Reilly, Genevieve Flock
Format: Article
Language:English
Published: Elsevier 2025-05-01
Series:Journal of Food Protection
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Online Access:http://www.sciencedirect.com/science/article/pii/S0362028X25000511
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author Dominique Pacitto-Reilly
Genevieve Flock
author_facet Dominique Pacitto-Reilly
Genevieve Flock
author_sort Dominique Pacitto-Reilly
collection DOAJ
description This study aimed to investigate the microbial safety of Vacuum Microwave Drying (VMD) and 30 days storage at 25 °C on survivability of Escherichia coli O157:H7 ATCC 43888 and Enterococcus faecium ATCC 8459 in a nutritionally minimal bar model and macronutrient bar model. Sodium alginate hydrocolloid gel bars were inoculated with each microorganism and underwent processing in a 2 kW VMD and subsequent storage at 25 °C for 10 days in sealed bags to determine the impact of VMD on bacteria without the influence of a nutritionally dense food matrix. Additionally, the effects of macronutrient concentration on organism survivability during processing and storage were tested using a peanut butter banana bar formulated to contain high carbohydrate, high protein, or high-fat content. The macronutrient bars were inoculated with each microorganism and underwent VMD with subsequent storage at 25 °C for up to 30 days in sealed bags. Results of the hydrocolloid gel model showed that in a nutritionally minimal food matrix, both microorganisms were susceptible to VMD with additional loss of each microorganism during storage. Results showed the entire loss of E. coli O157:H7 by day 10 of storage. In the macronutrient bar study, E. faecium had minimal susceptibility to VMD and storage at 30 days while E. coli O157:H7 had minimal susceptibility to VMD with greater susceptibility to storage for 30 days. There was a significant difference (p < 0.05) in log loss comparing E. coli O157:H7 VMD processed and unprocessed bars and minimal significance comparing E. faecium VMD processed and unprocessed bars. Water activity and moisture content at storage timepoints had no observed correlation with pathogen survivability in either study.
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spelling doaj-art-d116bf68ce4e4d1792dabbaa04bd9c512025-08-20T01:52:42ZengElsevierJournal of Food Protection0362-028X2025-05-0188610049910.1016/j.jfp.2025.100499Survivability of Escherichia coli O157:H7 ATCC 43888 and Enterococcus faecium ATCC 8459 in a Hydrocolloid Gel Bar Model and Macronutrient Bar Model in Response to Vacuum Microwave Drying and StorageDominique Pacitto-Reilly0Genevieve Flock1U.S. Army DEVCOM Soldier Center, 10 General Greene Avenue, Natick, MA 01760, USACorresponding author.; U.S. Army DEVCOM Soldier Center, 10 General Greene Avenue, Natick, MA 01760, USAThis study aimed to investigate the microbial safety of Vacuum Microwave Drying (VMD) and 30 days storage at 25 °C on survivability of Escherichia coli O157:H7 ATCC 43888 and Enterococcus faecium ATCC 8459 in a nutritionally minimal bar model and macronutrient bar model. Sodium alginate hydrocolloid gel bars were inoculated with each microorganism and underwent processing in a 2 kW VMD and subsequent storage at 25 °C for 10 days in sealed bags to determine the impact of VMD on bacteria without the influence of a nutritionally dense food matrix. Additionally, the effects of macronutrient concentration on organism survivability during processing and storage were tested using a peanut butter banana bar formulated to contain high carbohydrate, high protein, or high-fat content. The macronutrient bars were inoculated with each microorganism and underwent VMD with subsequent storage at 25 °C for up to 30 days in sealed bags. Results of the hydrocolloid gel model showed that in a nutritionally minimal food matrix, both microorganisms were susceptible to VMD with additional loss of each microorganism during storage. Results showed the entire loss of E. coli O157:H7 by day 10 of storage. In the macronutrient bar study, E. faecium had minimal susceptibility to VMD and storage at 30 days while E. coli O157:H7 had minimal susceptibility to VMD with greater susceptibility to storage for 30 days. There was a significant difference (p < 0.05) in log loss comparing E. coli O157:H7 VMD processed and unprocessed bars and minimal significance comparing E. faecium VMD processed and unprocessed bars. Water activity and moisture content at storage timepoints had no observed correlation with pathogen survivability in either study.http://www.sciencedirect.com/science/article/pii/S0362028X25000511E. coli O157:H7E. faeciumHydrocolloid gel modelMacronutrient bar modelVacuum microwave drying
spellingShingle Dominique Pacitto-Reilly
Genevieve Flock
Survivability of Escherichia coli O157:H7 ATCC 43888 and Enterococcus faecium ATCC 8459 in a Hydrocolloid Gel Bar Model and Macronutrient Bar Model in Response to Vacuum Microwave Drying and Storage
Journal of Food Protection
E. coli O157:H7
E. faecium
Hydrocolloid gel model
Macronutrient bar model
Vacuum microwave drying
title Survivability of Escherichia coli O157:H7 ATCC 43888 and Enterococcus faecium ATCC 8459 in a Hydrocolloid Gel Bar Model and Macronutrient Bar Model in Response to Vacuum Microwave Drying and Storage
title_full Survivability of Escherichia coli O157:H7 ATCC 43888 and Enterococcus faecium ATCC 8459 in a Hydrocolloid Gel Bar Model and Macronutrient Bar Model in Response to Vacuum Microwave Drying and Storage
title_fullStr Survivability of Escherichia coli O157:H7 ATCC 43888 and Enterococcus faecium ATCC 8459 in a Hydrocolloid Gel Bar Model and Macronutrient Bar Model in Response to Vacuum Microwave Drying and Storage
title_full_unstemmed Survivability of Escherichia coli O157:H7 ATCC 43888 and Enterococcus faecium ATCC 8459 in a Hydrocolloid Gel Bar Model and Macronutrient Bar Model in Response to Vacuum Microwave Drying and Storage
title_short Survivability of Escherichia coli O157:H7 ATCC 43888 and Enterococcus faecium ATCC 8459 in a Hydrocolloid Gel Bar Model and Macronutrient Bar Model in Response to Vacuum Microwave Drying and Storage
title_sort survivability of escherichia coli o157 h7 atcc 43888 and enterococcus faecium atcc 8459 in a hydrocolloid gel bar model and macronutrient bar model in response to vacuum microwave drying and storage
topic E. coli O157:H7
E. faecium
Hydrocolloid gel model
Macronutrient bar model
Vacuum microwave drying
url http://www.sciencedirect.com/science/article/pii/S0362028X25000511
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