Characterization of Bacillaceae associated with ropy bread

Ropy bread spoilage is a long-known phenomenon that primarily affects non-acidified white wheat bread. It is characterized by sticky, stringy degradation of the bread crumb, discoloration and a characteristic fruity odor reminiscent of rotting melons or pineapples. Increasing consumer demand for preservative-free products and the effects of climate change, such as rising ambient temperatures and extreme weather conditions, may contribute to an increase in the incidence of this spoilage phenomenon. While several species within the Bacillaceae family have been identified as causative agents, the precise mechanisms underlying rope spoilage remain poorly understood. Notably, rope spoilage is highly strain-specific, with different strains of the same species exhibiting distinct behaviors and spoilage dynamics. In particular, there is a lack of up-to-date data on the enzymatic and genetic factors that drive this spoilage phenomenon. Furthermore, the food safety aspects of bread contaminated with rope-forming bacteria, in particular the pathogenic potential of rope-forming strains and their impact on human health, have not been thoroughly investigated. In addition to unleavened white wheat bread, rope spoilage may also occur in other bakery products, including bread made from alternative grains such as those used in gluten-free bread, where similar spoilage dynamics may be observed. In-depth knowledge of the characteristics of spoilage relevant Bacillaceae is of paramount importance to the bakery industry. This project aims to address these knowledge gaps by characterizing the bacterial strains associated with rope formation, focusing on their enzymatic profiles and genetic backgrounds, assessing their pathogenic potential and, where relevant, investigating the susceptibility of alternative cereal-based breads to rope spoilage. The results will provide critical insights into the mechanisms of spoilage and support the production of high-quality bread while contributing to food safety and waste reduction.