Occurrence of Cronobacter spp. in retail foods

Abstract

Aims: To study the occurrence of Cronobacter spp. in foods and to investigate the phenotypic properties of the strains isolated. Methods and Results: A total of 53 strains of Cronobacter spp. isolated from 399 food samples were identified using conventional biochemical methods and MALDI‐TOF mass spectrometry. Foods of plant origin were the most frequently contaminated samples. No Cronobacter spp. were found in infant milk formula, wheat‐based infant food, pasteurized and raw cow milk, mincemeat, chicken, chickpea and potato dumpling powder. The individual species were identified as Cronobacter sakazakii (54·7%), Cronobacter malonaticus (28·4%), Cronobacter dublinensis (7·5%), Cronobacter muytjensii (7·5%) and Cronobacter turicensis (1·9%). Cronobacter sakazakii and C. malonaticus belong to biotype 1, 2, 2a, 3, 4 and 5, 5a, respectively. Cronobacter dublinensis strains were subdivided into biotypes 6 and 12. All strains were resistant to erythromycin and two of them were resistant to both erythromycin and tetracycline. Conclusions: Cronobacter spp. were isolated from various food samples pre‐eminently of plant origin and dried food ingredients. Significance and Impact of the Study: These findings will increase and detail our knowledge of the presence and diversity of Cronobacter spp. in foods.

Cronobacter spp. – opportunistic food-borne pathogens. A review of their virulence and environmental-adaptive traits

“…described Cronobacter strains recovered from foods that were resistant to cephalothin or ampicillin and susceptible to tetracycline. Hochel et al (2012) found that all Cronobacter isolates varied in their susceptibility to tetracycline. Muytjens & van der Ros-van de Repe (1986) examined Cronobacter susceptibility to 29 antimicrobial agents and found that Cronobacter were the most susceptible among other Enterobacteriaceae studied.…”

“…dried milk powder, dried meats, legumes, nuts, dried flours and spices) (Friedemann, 2007;Hochel et al, 2012) or drinking water (Lui et al, 2013). Although Cronobacter spp.…”

Lack of continuity between Cronobacter biotypes and species as determined using multilocus sequence typing

“…Despite the robustness of MLST, some researchers have continued to use biotyping to speciate their isolates [12, 13,14]. Presented here is a study investigating the reliability of the biotyping scheme for identifying the Cronobacter species.…”

Evaluation of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry for Rapid Identification of Bacteria in Processed Soybean Products

“…At a lower bacterial count (< 10 6 CFU/ml), background peaks became more prominent and affected spectrum matching. Although MALDI-TOF MS may become a popular identification method in food microbiology, there is little information on direct identification of bacteria in processed food products using MALDI-TOF MS (Angelakis et al, 2011;Böhme et al, 2011;Hochel et al, 2012). The separation of bacteria is conducted to harvest cells from complex food matrices that impede accurate detection (Benoit & Donahue 2003;Stevens & Jaykus, 2004).…”