Screening for Cronobacter species in powdered and reconstituted infant formulas and from equipment used in formula preparation in maternity hospitals.

BACKGROUND/AIMS: Cronobacter spp. have been identified as being of considerable risk to neonates. The occurrence of organisms in infant formulas is therefore of considerable interest. METHODS: The occurrence of Cronobacter spp. in infant feeds (formulas and fortified cow's milk) was determined using most probable number (MPN) analysis, and from formula preparation utensils. Ninety-nine samples were analyzed, of which 42 were unopened cans of powdered infant formula (PIF), 25 reconstituted infant formulas in feeding bottles, 27 utensils used in the preparation of infant formula and 5 samples of fortified cow's milk. Presumptive Cronobacter spp. isolates were identified using the 7 allele multilocus sequence typing (MLST) scheme. RESULTS: C. sakazakii, C. malonaticus and C. muytjensii were recovered from PIF. Although the incidence of Cronobacter in PIF was 29% (12/42), the level was low with an average of 0.54 MPN/100 g. According to MLST profiling, C. sakazakii was the most frequently isolated Cronobacter species, and C. sakazakii ST4 (associated with neonatal meningitis) was recovered from 2/42 PIF samples at 0.51 and 0.92 MPN/100 g. CONCLUSIONS: Cronobacter spp. can be isolated from PIF and therefore strict hygienic practices during PIF preparation are important to minimize neonate exposure and reduce the risk of severe infections.

Comparison of methods for the enumeration of Clostridium perfringens spores in water.

Four methods for enumerating Clostridium perfringens spores in water were evaluated: (1) the IMM (Iron Milk Medium) method (MPN); (2) the LS (Lactose Sulfite Broth) method (MPN); (3) the m-CP (membrane filtration Clostridium perfringens Agar) method (membrane filtration); and (4) the TSC (Tryptose Sulfite Cycloserine Agar) method (membrane filtration). The performance of these methods was compared with that of the DRCM (Differential Reinforced Clostridium Medium) method (MPN) as adopted by CETESB (Brazil's Environmental Sanitation Technology Company) for the analysis of C. perfringens spores in water. Statistical analysis was performed according to ISO 17994:2004 (Water Quality - Criteria for Establishing Equivalence between Microbiological Methods). The LS, m-CP, and TSC methods were considered not equivalent to the DRCM method, as they gave significantly lower results. The IMM showed inconclusive results and, according to ISO 17994:2004, analysis of a greater number of samples is needed to draw definitive conclusions comparing IMM and DRCM.

Bifidogenic effect of dietary fiber and resistant starch from leguminous on the intestinal microbiota of rats.

OBJECTIVES: The bifidogenic effect of leguminous containing diets on the intestinal microbiota of male Wistar rats was studied. METHODS: Isoprotein (12.2+/-0.3%) and isoenergetic (373.2+/-4.2 kcal/100 g) experimental diets, whose sources of dietary fiber and resistant starch were pea (Pisum sativum, L.), common bean (Phaseolus vulgaris, L.), chickpea (Cicer arietinum, L.), and lentil (Lens culinaris, Med.), and a control diet (casein+microcrystalline cellulose) were offered ad libitum to recently weaned male albino Wistar rats (16 rats/treatment) for 28 d. Cecal appendices were removed and analyzed for Bifidobacterium, Lactobacillus, Enterobacter, Bacteroides, Clostridium, and total anaerobes. RESULTS: The common bean diet showed the highest content of dietary fiber (17.0+/-0.2 g/100 g), which was significantly different (P<0.05) from the others. Resistant starch content was similar for all diets. The control and chickpea groups showed significantly higher consumption of diet and food conversion efficiency than the others. The leguminous-containing diets produced a larger mass of cecal material that was statistically different from the control group. The pea group presented the highest count of Bifidobacterium (9.4+/-0.7 log colony-forming units per gram of raw material), which was significantly different from the others, and the Lactobacillus count was similar for all groups. Animals fed leguminous-containing diets showed lower counts of Enterobacter and Bacteroides than did the control group and no statistical difference (P>0.05) was found between groups with respect to counts of Clostridium and total anaerobes. CONCLUSIONS: The pea and chickpea groups stood out from the others with respect to growth of Bifidobacterium, especially the pea group.