title: The effect of pH on the initiation of growth of cottage cheese spoilage bacteria.
abstract: The influence of pH on strains of Pseudomonas spp. and Enterobacter agglomerans that cause spoilage of cottage cheese varieties during storage at 7 degrees C has been investigated. In a culture medium adjusted to the required pH with HCl, 57 of 64 strains of Pseudomonas spp. grew at pH 4.8 when incubated at 7 degrees C but a very low proportion of strains grew at pH 4.7 or pH 4.6 and none at pH 4.5. At 20 degrees C some of the pseudomonads grew at pH 4.4. Three out of nine strains of E. agglomerans grew at pH 3.8 when incubated at 7 degrees C and at pH 3.6 when incubated at 20 degrees C. In cultures of E. agglomerans at controlled pH and 20 degrees C, after a lag phase the doubling time at pH 4.1 was 2 h, and at pH 7.0 was 1.4 h.
authors.affiliation: Agricultural and Food Research Council, Institute of Food Research, Norwich, U.K.
authors.forename: T F
authors.initials: TF
authors.lastname: Brocklehurst
authors.forename: B M
authors.initials: BM
authors.lastname: Lund
mesh_terms: D002611:Cheese; D003470:Culture Media; D004754:Enterobacter / Q000254:growth & development*; D004755:Enterobacteriaceae / Q000254:growth & development*; D005516:Food Microbiology; D005519:Food Preservation; D006863:Hydrogen-Ion Concentration; D011549:Pseudomonas / Q000254:growth & development*; D013696:Temperature
chemical_list: D003470:Culture Media