title: Growth of Salmonella enterica and Staphylococcus aureus in no-knead bread dough during prolonged yeast fermentation.
abstract: A convenient bread making method involving prolonged fermentation of no-knead (nonkneaded) dough has become popular in recent years. In the present study, the microbial safety of no-knead dough made with a 375:325:5:1 weight ratio of flour, water, salt, and bread yeast was investigated. Three brands of dehydrated yeast were used for this study. The growth of inoculated Salmonella enterica and Staphylococcus aureus in no-knead dough during fermentation was significant (P<0.05), regardless of yeast brand. The multiplication rates of S. enterica in the initial 12 h and S. aureus over the entire 24 h of fermentation were positively correlated with fermentation temperatures of 21 to 38°C (P<0.005; r≥0.996). Mean counts of S. enterica increased by 0.5, 1.5, 1.9, and 2.4 log CFU/g, respectively, after 6, 12, 18, and 24 h of fermentation at 21 °C. The level of S. aureus increased by 0.4, 1.1, 1.7, and 2.2 CFU/g, respectively, after 18 h of fermentation at 21, 27, 32, and 38 °C. Because prolonged fermentation permits substantial growth of infectious and/or toxin-producing foodborne pathogens, the making of slow-rise, no-knead bread may compromise consumer kitchen sanitation and food safety.
authors.affiliation: Agriculture Research Station, Virginia State University, Petersburg, Virginia 23806, USA. spao@vsu.edu
authors.forename: Steven
authors.initials: S
authors.lastname: Pao
authors.forename: Chyer
authors.initials: C
authors.lastname: Kim
authors.forename: Larry
authors.initials: L
authors.lastname: Jordan
authors.forename: Wilbert
authors.initials: W
authors.lastname: Long
authors.forename: Paula
authors.initials: P
authors.lastname: Inserra
authors.forename: Brian
authors.initials: B
authors.lastname: Sayre
mesh_terms: D001939:Bread / Q000382:microbiology*; D003257:Consumer Product Safety; D005285:Fermentation; D005506:Food Contamination / Q000032:analysis*; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D006801:Humans; D019779:Salmonella enterica / Q000254:growth & development*; D013211:Staphylococcus aureus / Q000254:growth & development*; D013696:Temperature; D013997:Time Factors; D015003:Yeasts / Q000378:metabolism