Fate of gram-positive bacteria in reconditioned, pork-processing plant water.
This study investigated the responses of Enterococcus faecium (ATCC 19433), Staphylococcus aureus (196E), and Listeria monocytogenes Scott A in water from a local meat-processing plant. Each bacterium was added to a starting count of 3 log10 CFU/ml and held from 5 to 28 degrees C. At intervals (0, 2, 7, 14, and 21 days), aliquots were plated on appropriate selective agars. In contrast to the gram-negative bacteria studied previously and which grew, the three gram-positive bacteria survived with some slight increase in number in only nonchlorinated, reconditioned water, either filtered (0.22 microm pore size) or nonfiltered. The presence of chlorine in either potable or reconditioned water contributed to the rapid decline in viable counts for all three bacteria. These results further emphasize the importance of residual chlorine in preventing the growth of these gram-positive bacteria in potable and reconditioned waters.
Palumbo
S A
SA
U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania 19038, USA. spalumbo@arserrc.gov
Pickard
A
A
Call
J E
JE
D000818:Animals; D002713:Chlorine / Q000494:pharmacology; D015169:Colony Count, Microbial; D003470:Culture Media; D005511:Food Handling; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000254:growth & development*; D008460:Meat; D008851:Micropore Filters; D013552:Swine; D013696:Temperature; D014867:Water / Q000737:chemistry; D014871:Water Microbiology
D003470:Culture Media; D014867:Water; D002713:Chlorine