# Advances in Fermentation Technology: A Focus on Health and Safety
## 2 Microbial Control of the Pathogens' Growth--Biocontrol Strategies
### Potential Health Hazards in Traditional Fermentation
#### 2.1.1 Pathogenic Contamination  
Pathogenic contamination remains a significant concern in traditional fermentation practices, mainly through foodborne outbreaks with varying incidence rates influenced by regional factors, production practices, and food types. In 2021, 28 multistate foodborne outbreaks in the United States were specifically attributed to contaminated fermented, primarily involving Shiga toxin-producing _E. coli_ (STEC, 14%), Listeria (29%), and Salmonella (57%), causing 15 deaths, 496 hospitalizations, surprisingly 1740 illnesses [11]. An outbreak of Shiga toxin-producing _E. coli_ (STEC) O157 associated with kimchi in Canada involved 14 confirmed cases, with 91% of affected individuals (10 out of 11 interviewed) reporting consumption of a single brand (Kimchi Brand A), strongly implicating that product as the outbreak source [12]. The European Food Safety Authority (EFSA) reported that from 2018 to 2022, fermented foods represented approximately 1.2% of foodborne outbreak incidents in the EU [13]. Specific fermented foods that are particularly susceptible to microbial contamination include animal products (meat and dairy products), cereal-based fermentations, and fermented fruits and vegetables (kimchi, sauerkraut). The risk of outbreaks is heightened by factors such as inadequate hygiene practices, unregulated fermentation conditions, and the use of contaminated raw materials, all of which can significantly promote the growth of pathogenic bacteria in ready-to-eat foods [14]. Studies have indicated the high prevalence rates of _S. aureus_ (46.3%), _Salmonella_ (26.0%), and _E. coli_ (33.8%) [15]. Recent studies have reported that traditionally fermented dairy products have substantial issues with microbiological safety, highlighting the need for improved techniques and regulations to ensure their safety and quality. For instance, a study in Iran revealed that 65% of traditional dairy samples were contaminated with at least one pathogenic bacteria, including _Listeria monocytogenes_ (27.5%) and _Staphylococcus aureus_ (59.5%) [16]. Similarly, research in Zambia identified pathogens in raw milk used for Mabisi production, although the final products met safety limits [17]. In Portugal, _L. monocytogenes_ and coagul-positive staphylococci, exceeding 10\({}^{4}\) CFU/g, were detected in 15.6% and 16.9% of cured raw milk cheeses, respectively [18]. Additionally, an Ethiopian study found _S. aureus_ in 24.6% of raw milk samples and 17.5% of yoghurt samples, with 38.5% of methicillin-resistant isolates [19]. Pathogenic bacteria, such as _L. monocytogenes_ and _Staphylococcus aureus_, have been reported in Portuguese fermented sausages. Factors contributing to their proliferation include delayed fermentation processes and insufficient acidification [20]. Pathogenic contamination is a significant concern in dairy and other fermented products, including soy products, fruits, and vegetables. For instance, research has indicated that contaminants are particularly prevalent in fermented soy products, highlighting the need for effective control measures. These measures should encompass rigorous screening of raw materials, the optimization of fermentation processes, and the incorporation of specific inhibitors during fermentation to reduce contaminant levels significantly. Several enteric pathogens, such as _Clostridium botulinum_ and _E. coli_, have been identified in traditional fermented foods from Northeast India [21]. In addition, _Bacillus cereus_ has shown significant prevalence in Korean fermented soybean products, with detection rates reaching up to 73.1% in the fermented paste known as doenjang [22]. A study that evaluated the microbiological hazards in fermented vegetables sold in wet markets in Cambodia revealed alarming rates of contamination of _Enterococcus_ spp. (34%), followed by _Bacillus_ spp. (31%), other coliform bacteria (24%), and _E. coli_ (10%).