Applicability of Enterobacteriaceae and coliforms tests as indicators for Cronobacter in milk powder factory environments

• Published in: Food microbiology 2021-04, Vol.94, p.103642-103642, Article 103642
• Main Authors: Craven, Heather, McAuley, Catherine, Hannah, Murray, Duffy, Lesley, Fegan, Narelle, Forsythe, Stephen
• Format: Article
• Language: English
• Subjects: coliforms; Cronobacter; Enterobacteriaceae; indicator; milk powder factory environment
• ISSN: 0740-0020; 1095-9998
• DOI: 10.1016/j.fm.2020.103642

The emergence of Cronobacter as an important potential pathogen for newborn children and its occurrence in powdered infant formulae has generated a need to develop new management practices for this food group. This includes reduction of the prevalence of Cronobacter in manufacturing environments which can be a source of Cronobacter. This study was performed to assess the suitability of qualitative and quantitative Enterobacteriaceae and coliforms indicator tests for the presence and prevalence of Cronobacter. Environmental swabs (205) from five milk powder factories were examined. The qualitative indicator tests had good sensitivity but they lacked specificity for reliable routine use. Logistic regression analyses revealed a significant relationship between the quantitative indicator tests and Cronobacter prevalence, where the Enterobacteriaceae count was a slightly stronger predictor for Cronobacter than the coliforms count. The optimum test sensitivity (81%) and specificity (66%) was obtained when the indicator count thresholds were set at ≥1 cfu/cm2. However, since 11% of samples were Cronobacter positive when counts of Enterobacteriaceae and coliforms were less than 1 cfu/cm2, specific testing for Cronobacter is advised in addition to Enterobacteriaceae testing to minimise risk of transfer of Cronobacter from the factory environment into powdered infant formulae products. •New biometrical tests assessed indicators for Cronobacter in milk powder factories.•Enterobacteriaceae and coliforms were modelled with environmental Cronobacter data.•Qualitative tests were sensitive but not specific Cronobacter indicators.•Quantitative tests informed Cronobacter prevalence but not all locations.•Specific tests are needed to find niches and minimise Cronobacter spread to product.