Non-starter Lactobacillus strains as adjunct cultures for cheese-making: “in vitro” characterization and performance in two model cheeses

BRIGGILER-MARCÓ, M.; CAPRA, M.L.; QUIBERONI, A.; VINDEROLA, G.; REINHEIMER, J.; HYNES, E.

INTERNATIONAL DAIRY JOURNAL

Elsevier

Año: 2007 vol. 40 p. 4532 - 4542

0958-6946

Nonstarter lactic acid bacteria are the main uncontrolledfactor in today’s industrial cheese making andmay be the cause of quality inconsistencies and defectsin cheeses. In this context, adjunct cultures of selectedlactobacilli from nonstarter lactic acid bacteria originappear as the best alternative to indirectly controlcheese biota. The objective of the present work wasto study the technological properties of Lactobacillusstrains isolated from cheese by in vitro and in situassays. Milk acidification kinetics and proteolytic andacidifying activities were assessed, and peptide mappingof trichloroacetic acid 8% soluble fraction of milkcultures was performed by liquid chromatography. Inaddition, the tolerance to salts (NaCl and KCl) andthe phage-resistance were investigated. Four strainswere selected for testing as adjunct cultures in cheesemaking experiments at pilot plant scale. In in vitroassays, most strains acidified milk slowly and showedweak to moderate proteolytic activity. Fast strains decreasedmilk pH to 4.5 in 8 h, and continued acidificationto 3.5 in 12 h or more. This group consisted mostlyof Lactobacillus plantarum and Lactobacillus rhamnosusstrains. Approximately one-third of the slowstrains, which comprised mainly Lactobacillus casei,Lactobacillus fermentum, and Lactobacillus curvatus,were capable to grow when milk was supplementedwith glucose and casein hydrolysate. Peptide mapswere similar to those of lactic acid bacteria consideredto have a moderate proteolytic activity. Most strainsshowed salt tolerance and resistance to specificphages. The Lactobacillus strains selected as adjunctcultures for cheese making experiments reached 108cfu/g in soft cheeses at 7 d of ripening, whereas theyreached 109 cfu/g in semihard cheeses after 15 d ofripening. In both cheese varieties, the adjunct culturepopulation remained at high counts during all ripen-Received March 8, 2007.Accepted June 13, 2007.1Corresponding author: ehynes@fiqus.unl.edu.ar4532ing, in some cases overcoming or equaling primarystarter. Overall, proximate composition of cheeseswith and without added lactobacilli did not differ; however,some of the tested strains continued acidifyingduring ripening, which was mainly noticed in softcheeses and affected overall quality of the products.The lactobacilli strains with low acidifying activityshowed appropriate technological characteristics fortheir use as adjunct cultures in soft and semihardcheeses.