Survival of Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes in cranberry juice concentrates at different oBrix levels.
Survival of Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes was evaluated in cranberry juice concentrates to determine if a 5-log reduction could be achieved without any other treatment. Inactivation at 0 degrees C in concentrates with different oBrix levels was determined for a five-strain composite of the individual pathogens in two physiological states. In concentrates at 18 to 46 oBrix (pH 2.2 to 2.5), all three pathogens (stationary-phase or acid-adapted cells) showed at least a 5-log reduction after a 6- or 24-h incubation. At 14 oBrix (pH 2.5), a reduction greater than 5 log was obtained for L. monocytogenes and Salmonella after up to 24 h of incubation, but for E. coli O157:H7, 96 h of incubation was needed to consistently obtain a reduction greater than 5 log. All three pathogens in the stationary phase survived longer than in the acid-adapted phase under the same conditions. The most resistant was stationary-phase E. coli O157:H7, and the most sensitive was acid-adapted L. monocytogenes. The rate of pathogen destruction increased with increasing oBrix level of the juice concentrate, which suggests that concentrated acids and/orsome intrinsic compounds may play an important role in the bactericidal effects of cranberry juice concentrates.
Enache
Elena
E
Center for Technical and Laboratory Services, Grocery Manufacturers/Food Products Association, 1350 I Street N.W., Suite 300, Washington, DC 20005, USA. eenache@fpa-food.org
Chen
Yuhuan
Y
D000222:Adaptation, Physiological; D001628:Beverages / Q000382:microbiology*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D019453:Escherichia coli O157 / Q000254:growth & development* / Q000502:physiology; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008089:Listeria monocytogenes / Q000254:growth & development* / Q000502:physiology; D012475:Salmonella / Q000254:growth & development* / Q000502:physiology; D013696:Temperature; D013997:Time Factors; D029799:Vaccinium macrocarpon