Influence of Nonstarter Bacteria on Calcium Lactate Crystallization on the Surface of Cheddar Cheese

Abstract

Cheddar cheese was manufactured under conditions inducing calcium lactate crystal formation. The cheeses were analyzed for lactic acid and nonstarter bacteria and examined for crystal growth. There was a strong correlation between calcium lactate crystallization, lactic acid enantiomer, and numbers of nonstarter bacteria. As the cheese aged, the nonstarter bacteria counts increased concomitantly with a change from a predominantly L(+)-lactic acid in the cheese to a racemic mixture of L(+)- and D(−)-lactic acid. Enzymatic analysis of the crystals and cheese with crystals showed that both contained a racemic mixture of lactic acid. Lactobacilli able to racemize lactic acid were isolated from these cheeses. A pure culture of a racemase-positive Lactobacillus was added to milk for cheese making. The resultant cheeses were initially stored at 7.2 and 10°C. After 1 mo the cheeses were cut and packaged with or without vacuum and stored at 7.2, 10, or 3.3°C. Cheeses stored at 3.3°C (regardless of initial storage temperature) developed crystals to a much greater extent than cheese stored at 7.2 or 10°C. Vacuum packaging curtailed the development of crystals. No crystals were observed on control (no lactobacilli added) cheeses. Control of the growth of nonstarter bacteria and vacuum packaging appear to be important in the prevention of calcium lactate crystallization. © 1990, American Dairy Science Association. All rights reserved.