Survey of bacterial populations present in US-produced linerboard with high recycle content.
OBJECTIVE
To survey paperboard products from 17 US mills for bacterial populations and for bacteria potentially harmful to human health.


RESULTS
Culturable aerobic bacteria were isolated from paperboard products using selective and nonselective medium. Resulting colonies from samples from three regions of the United States were identified using fatty acid methyl ester analysis. Percentages of bacteria species found were Bacillus megaterium (47), Bacillus licheniformis (15), Bacillus pumilus (12), Paenibacillus macerans (5), Paenibacillus pabuli (3), Bacillus subtilis (2), Bacillus cereus (2), Bacillus coagulans (1), Bacillus circulans (1), Bacillus brevis (1), Bacillus thuringiensis (1), Paenibacillus polymyxa (1), Cellulomonas turbata (1), Cellulomonas flavigena (1), unidentified Bacillus sp. (3) and unidentified bacteria (1).


CONCLUSIONS
Recycled paperboard contained high populations of bacteria, and a positive correlation was found between recycle content and bacterial populations. Escherichia coli, Salmonella, Shigella or confirmed coliform bacteria were not found in any product.


CONCLUSIONS
Populations of bacteria did not differ significantly from original counts over a 4-month period of dry storage, indicating that bacteria persist in paperboard over long periods and may re-enter the recycling process. The predominance of heat-tolerant endospore-forming bacteria explains the high bacteria counts found in paperboard made from recycled materials.
Namjoshi
K
K
Institute of Paper Science and Technology, Georgia Institute of Technology, Atlanta, GA 30332-0620, USA.
Johnson
S
S
Montello
P
P
Pullman
G S
GS
D001420:Bacteria, Aerobic / Q000302:isolation & purification*; D015169:Colony Count, Microbial; D003247:Conservation of Natural Resources; D003252:Construction Materials / Q000382:microbiology*; D003470:Culture Media; D010209:Paper
D003470:Culture Media