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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOP METHODS TO ASSESS AND IMPROVE POULTRY AND EGG QUALITY

Location: Quality and Safety Assessment Research Unit

Title: Photocatalytic inactivation of bacteria from spoiled raw chicken carcasses in aqueous suspensions by TiO2 nanoparticles

Authors
item Wang, Jiamei -
item ZHUANG, HONG
item HINTON, JR., ARTHUR
item Zhang, Jianhao -

Submitted to: International Food Technology Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: February 5, 2013
Publication Date: July 13, 2013
Citation: Wang, J., Zhuang, H., Hinton Jr, A., Zhang, J. 2013. Photocatalytic inactivation of bacteria from spoiled raw chicken carcasses in aqueous suspensions by TiO2 nanoparticles [abstract]. International Food Technology Meeting Abstracts.

Interpretive Summary: Bacterial spoilage is a major cause of reduced shelf life of fresh poultry; therefore, decreasing contamination by spoilage bacteria could increase the shelf life of these products. Titanium dioxide (TiO2) nanoparticles in the presence of UVA light possess antibacterial activities towards several bacteria; however, there is a lack of published reports on the antimicrobial activity of TiO2 against spoilage bacteria associated with fresh poultry carcasses. The objective of our study was to investigate the bactericidal activity of TiO2 in the presence of UVA light towards Gram negative (Pseudomonas fluorescens) and Gram positive (Macrococcus caseolyticus) spoilage bacteria isolated from fresh poultry. Different concentrations (0.2-0.8g/L) of TiO2 nanoparticles were mixed with suspensions of 106-108 cfu/mL of P. fluorescens or M. caseolyticus. The bacterial suspensions were exposed to 300-500 µW/cm2 of UVA light for a total of 150 min, and viable bacteria in the suspensions were then enumerated. Results indicated that TiO2 is bactericidal towards both spoilage bacteria in the presence of UVA. In suspensions containing 107 cfu/mL of each bacterium, there was a 4 log reduction of P. fluorescens after150 min and a 7 log reduction of M. caseolyticus in less than 120 min. Reducing cfu/ml of bacteria in the suspensions reduced the time required for photocatalytic inactivation by TiO2 and UVA. Additionally, increased light intensity intensified TiO2 antimicrobial activity. Reduction of P. fluorescens by TiO2 was 100-fold greater with 500 µW/cm2 of UVA than with 300 µW/cm2. The bacterial isolates also exhibited differences in susceptibility towards the bactericidal activity of TiO2. Fewer cfu/ml of P. fluorescens than M. caseolyticus were recovered from suspensions treated with 0.8 g/L of TiO2. These results suggest that under UVA light TiO2 effectively inactivates both Gram negative and G positive bacteria associated with the spoilage of fresh poultry.

Technical Abstract: Bacterial spoilage is a major cause of reduced shelf life of fresh poultry; therefore, decreasing contamination by spoilage bacteria could increase the shelf life of these products. Titanium dioxide (TiO2) nanoparticles in the presence of UVA light possess antibacterial activities towards several bacteria; however, there is a lack of published reports on the antimicrobial activity of TiO2 against spoilage bacteria associated with fresh poultry carcasses. The objective of our study was to investigate the bactericidal activity of TiO2 in the presence of UVA light towards Gram negative (Pseudomonas fluorescens) and Gram positive (Macrococcus caseolyticus) spoilage bacteria isolated from fresh poultry. Different concentrations (0.2-0.8g/L) of TiO2 nanoparticles were mixed with suspensions of 106-108 cfu/mL of P. fluorescens or M. caseolyticus. The bacterial suspensions were exposed to 300-500 µW/cm2 of UVA light for a total of 150 min, and viable bacteria in the suspensions were then enumerated. Results indicated that TiO2 is bactericidal towards both spoilage bacteria in the presence of UVA. In suspensions containing 107 cfu/mL of each bacterium, there was a 4 log reduction of P. fluorescens after150 min and a 7 log reduction of M. caseolyticus in less than 120 min. Reducing cfu/ml of bacteria in the suspensions reduced the time required for photocatalytic inactivation by TiO2 and UVA. Additionally, increased light intensity intensified TiO2 antimicrobial activity. Reduction of P. fluorescens by TiO2 was 100-fold greater with 500 µW/cm2 of UVA than with 300 µW/cm2. The bacterial isolates also exhibited differences in susceptibility towards the bactericidal activity of TiO2. Fewer cfu/ml of P. fluorescens than M. caseolyticus were recovered from suspensions treated with 0.8 g/L of TiO2. These results suggest that under UVA light TiO2 effectively inactivates both Gram negative and G positive bacteria associated with the spoilage of fresh poultry.

Last Modified: 9/29/2014
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