# Probiotics in the Sourdough Bread Fermentation: Current Status
## 6 General Regulation for Microbes Used in Sourdough Bread  
Searching for rules that maintain food safety is a critical concern due to the growing use of microorganisms as foods or probiotics. At this moment, there is an effort at Codex Alimentarius to harmonize rules for probiotics and the use of microorganisms in food [251].  
In the United States, there are rules defined by the Food and Drug Administration (FDA) for the use of microorganisms in food production. It is necessary to qualify as a Generally Recognized as Safe for Use (GRAS) microorganism [252]. In Brazil, the biological fermenting mixtures and their microbial content are classified as a supporting and processing agent and are exempted from registration by ANVISA [253]. However, food with nutritional allegations or probiotic use needs to be registered [253], and microorganisms isolated from national raw materials, or related territory, are recognized as national genetic patrimony [254], and they need to be registered too.  
The requirements for a microorganism to be considered GRAS include taxonomic identification, absence of virulence, enterotoxins, hemolytic activity, and transferable antibiotic resistance genes. A probiotic microorganism still needs to prove stress tolerance (low pH, gastric enzymes, bile salts) up to levels found in the intestine, as well as adhesion capacity and antipathogenic activity, and to be approved in clinical trials [255]. Moreover, FAO/WHO advises in its guidelines that the evaluation of probiotics should be done using molecular information from strains, because the probiotic properties are related to this level of identification [256].  
In France, since 1993, a law specifies the characteristics of sourdough bread, such as pH 4.3, acetic acid 900 ppm, at least, with sourdough consisting of lactic acid bacteria and yeasts. It is possible to add _Saccharomyces cerevisiae_ to a maximum of 0.2% on the flour weight. If sourdough is dry, it needs at least one billion live food bacteria and one to ten million live yeasts per gram [257].  
In Europe, since 1997, with the novel food regulation, all food that started to be produced after 15 May 1997 is considered a novel food and has specific rules to be followed [258]. For microorganisms usually found in sourdough and used as a starter, it is  
Figure 4: Some possible interactions of wheat proteins. (**A**)-low water content. (**B**)-baking mixture with optimal water content, based on the work of [PERSON] et al. and [PERSON] [249; 250].  
challenging to define it as a novel food because sourdough predates 1997 [259]. Therefore, if the starter used in the sourdough fermentation is unusual or has some additional novel properties, it could be considered a novel food. For instance, UV-treated baker's yeast (_Saccharomyces cerevisiae_) has been considered a novel food since 2017 because it is alleged to increase vitamin D2 [260]. Moreover, the EU1151/2012 recognizes that baker products could have a geographical denomination [11].  
Regarding microorganism patents, the United States, Japan, Europe, India, and participants of The Trade-related Aspects of Intellectual Property Rights (TRIPS) agreement consider that microorganisms should be patented [261]. However, Brazil, for instance, allows patenting only for genetically modified microorganisms [262].