Gain insight into survival, growth of E. sakazakii in infant cereals.
E. sakazakii infections in infants and children up to four years of age have been associated with their consumption of infant formulas. The pathogen's ability to survive nad grow in infnat cereals as affected by water activity (aW), temperature nad reconstitution liquid is unknown.University of Georgia scientists undertook a study to determine the survival characteristics of E. sakazakii at 4 C to 30 C in infant cereal at aW 0.23 to 0.88. Their results provide new insights into the behavior of E. sakazakii as affected by conditions under which dry and reconstituted cereals are held during commercial distribution and in hospital and home settings. This information is helpful when assessing and managing the risk of E. sakazakii infection associated with infant cereals.
The scientists inoculated rice, barley and mixed-grain infant cereals at aW 0.23 to 0.88 with 5.3 log CFU per g of E. sakazakii and held them at 4 C, 21 C and 30 C. Populations were monitored for up to six months.
Rice, rice with banana, and oatmeal infant cereals were reconstituted with water, milk or apple juice, inoculated with E. sakazakii at 0.55 CFU per ml, and held at 4 C, 12 C, 21 C and 30 C for up to 72 hours. Populations were determined at 4-hour to 24-hour intervals. The investigators correlated the rate of decrease in viable E. sakazakii levels in dry cereals with increases in water activity and storage temperature.
The bacteria did not grow in reconstituted cereals stored at 4 C or in cereals reconstituted with apple juice and stored at 12 C and 21 C. Growth occurred in cereals reconstituted with water or milk and stored at 12 C, 21 C and 30 C for 48 hours, 12 hours and 8 hours, respectively. After reaching 8 to 9 log CFU per mL of reconstituted cereal, populations decreased, concurrent with decreases in pH levels.
Further information. Larry Beuchat, Center for Food Safety, Department of Food Science and Technology, 1109 Experiment St., Melton Building, University of Georgia, Griffin, GA 30223; phone: 770-412-4740; fax: 770-229-3216; email: lbeuchat@uga.edu.
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| Publication: | Microbial Update International |
|---|---|
| Date: | Feb 1, 2007 |
| Words: | 352 |
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