Incidence, Survival, and Growth of Enterobacter sakazakii in Infant Formula

Abstract

Enterobacter sakazakii has been implicated in a severe form of neonatal meningitis. Although studies have failed to identify an environmental source for the organism, dried infant formula has been implicated in outbreaks and sporadic cases of E. sakazakii meningitis. The high mortality rate (50 to 75%), the severity of the infection in infants, and the lack of information on the incidence, survival, and growth of E. sakazakii in foods led to this study. Experiments were undertaken to determine the incidence of E. sakazakii in dried infant formula, the temperature range for growth, and the growth characteristics of E. sakazakii in reconstituted dried infant formula. Strains of E. sakazakii were isolated from dried infant formula available on the Canadian retail market. The prevalence varied from 0 to 12% in samples from five different companies. For both clinical and food isolates, minimum growth temperatures of 5.5 to 8.0°C were observed by using a temperature-gradient incubator. The potential growth of E. sakazakii was followed by using a mixture of food and clinical isolates in three different formulas incubated at 4, 10, and 23°C. Average generation times were 40 min at 23°C and 4.98 h at 10°C. E. sakazakii strains did not grow at 4°C and began to die off during storage at this temperature. The results of this study stress the importance of using aseptic methods and proper temperature control in the preparation, use, and storage of dried infant formula.

Cronobacter sakazakii (Enterobacter sakazakii): An Emerging Foodborne Pathogen

“…Species of this genus can grow at temperatures between 6-47 °C with an optimum growth temperature of 39 °C 13 . However, some strains are inhibited at temperatures above 44 °C 1, 25 and some strains are capable of growing at 5 °C 26 . Pigment production and colony size on tryptone soy agar (TSA) are greatly influenced by the incubation temperature.…”

“…The first known cases of Cronobacter infections were two cases of meningitis in neonates 66 . These pathogens have been shown to cause a severe form of neonatal meningitis which is an acute inflammation of the membranes surrounding the brain and spinal cord 26 . Cronobacter strains have also been isolated from infants associated with necrotizing enterocolitis which is caused by IJBAR (2013) 04 (06) www.ssjournals.com infection of the intestines.…”

Time–temperature profiles of infant milk formula in hospitals and analysis of Enterobacter sakazakii growth

“…Data on these infants indicated most of them were pre-terme, below 37 weeks gestation, and had a low birth-weight, below 2500 g, or peripartum complications (Lai, 2001). Mortality rates of 40 to 80% (Nazarowec-White, Farber, 1997a;Edelson-Mammel, Buchanan, 2004) have been reported. Survivors often suffer from serious brain damage such as hydrocephalus, quadriplegia and late neural development.…”

Ocorrência de Enterobacter sakazakii no ambiente de lactários de Maternidades da Grande São Paulo

“…Entretanto, E. sakazakii não fermenta D-sorbitol e produz deoxirribonuclease e o-glucosidase (Kleiman et ai., 1981;NazarowecWhite;Farber, 1997c).…”

“…A freqüência de contaminação de latas de fórmula infantil desidrata por E. sakazakii é muito baixa, conforme já verificado por ( Nazarowe-White; Farber, 1997c;Forsythe, 2004;Gillio, 2006).…”