Texture and microflora of vallagret cheese during maturation

Abstract

Vallagret is a unique Jarlsberg-like cheese that combines characteristics of Cheddar and Swiss cheeses. The objectives of this study were to elucidate the stress and strain behaviour of young (1 week) and mature (20 weeks) vallagret cheese and to enumerate the microflora of young and matured cheeses. The large deformation properties of vallagret cheese were determined using an Instron universal testing machine. Lactococci were enumerated using M17 agar. Lactobacilli and Leuconostoc mesenteroides ssp. cremoris were enumerated on Lactobacillus selective (LBS) agar while the aerobic microorganisms were enumerated using plate count agar. Fracture stress decreased significantly from 0.52 MPa in young cheese to 0.11 MPa in the matured samples and fracture strain decreased significantly from 87% in young cheese to 41% in matured cheese. Aerobic microorganisms and lactococci decreased on maturation while the numbers of lactobacilli and Leuconostoc mesenteroides ssp. cremoris increased over the 20-week maturation period. Maturation affected the microbial counts of vallagret cheese. On maturation, vallagret cheese became softer and had lowered resistance to fracture.