Spoilage of bread by bacillus

Rope-Producing Strains of Bacillus spp. from Wheat Bread and Strategy for Their Control by Lactic Acid Bacteria

“…Prevention of growth of approximately 10 4 rope-producing B. subtilis G1 spores per cm 2 on bread slices for more than 15 days was observed when heat-treated cultures of Lactobacillus plantarum E5 and Leuconostoc mesenteroides A27 were added. Growth of B. subtilis G1 occurred after 7 days in breads started with Saccharomyces cerevisiae T22, L. plantarum E5, and L. mesenteroides A27.Ropiness is bacterial spoilage of bread that initially occurs as an unpleasant fruity odor, followed by enzymatic degradation of the crumb that becomes soft and sticky because of the production of extracellular slimy polysaccharides (15,43).The species involved in this type of spoilage of bread are primarily Bacillus subtilis and occasionally Bacillus licheniformis, Bacillus pumilus, and Bacillus cereus, even though some rope-producing Bacillus isolates are often not identified at the species level (9,22,41). It is well known that species differentiation within the genus Bacillus is very difficult because of the large number of species and the often incomplete descriptions of a number of newly reported species (19).…”

“…Ropiness is bacterial spoilage of bread that initially occurs as an unpleasant fruity odor, followed by enzymatic degradation of the crumb that becomes soft and sticky because of the production of extracellular slimy polysaccharides (15,43).…”

“…Spores of B. subtilis have been isolated from ropy bread, raw materials, and bakery environments and also from additives, including yeast, bread improvers, and gluten (4,9,33,43). B. subtilis spores are heat resistant and can survive during baking in the core of the crumb, where the maximum temperature is 97 to 101°C for a few minutes (31,33).…”

Fermentation Processes Using Lactic Acid Bacteria Producing Bacteriocins for Preservation and Improving Functional Properties of Food Products

“…Figure 4 illustrates an example of -ropy bread. B. subtilis spores have been isolated from ropy bread, meanwhile contamination of Bacillus have been reported to originate from raw materials, bakery environments and also from additives, including yeast, bread improvers, and gluten (Thompson et al, 1993;Rosenkvist and Hansen, 1995;Collins et al, 1991;Sorokulova et al, 2003;Bailey and von Holy, 1993). B.subtilis spores being heat resistant can survive the baking process, since the maximum temperature in the loaf centre remains 97 o C to 101 o C for a few minutes (Östman, 2002;Rosenkvist and Hansen, 1995).…”

“…Under stressful environmental conditions, the cells produce oval endospores that can stay dormant for extended periods (Ravel and Fraser, 2005;Kunst et al, 1997). Bacteria belonging to the genus Bacillus are capable of causing economic losses to the baking industry due to the food spoilage condition known as rope (Valerio et al, 2008;Thompson et al, 1993 (Şimşek et al, 2006;Rosenkvist and Hansen, 1995;Collins et al, 1991). These strains are also known to be foodborne pathogens when present at levels of 105 CFU/g in bread crumb (Kramer and Gilbert, 1989).…”