High-quality chili sauce starter should originate from naturally fermented, high-quality chili sauce. The quality of the starter directly affects the sensory characteristics of the final product, such as taste, flavor, and aroma. Therefore, superior starter strains are crucial for developing chili sauce starters. Naturally fermented chili sauces have a unique flavor, which is inseparable from the fermentation process of microorganisms. Naturally inoculated chili sauces contain a wide variety of microorganisms and rich enzyme systems, achieving complementarity in enzyme systems and metabolic products. However, natural selection makes it difficult to maintain consistent product quality, hindering the requirements of modern large-scale production. Currently, a large portion of the microbial strains used in chili sauce production are derived from the mixed fermentation of pure microorganisms. This approach maintains a basic consistency in product quality and ensures that the flavor and aroma of traditional chili sauce products remain unchanged.

Molds play a vital role in chili sauce production. These include Aspergillus oryzac, Aspergillus niger, Aspergillus sojac, and Mucor pp. Since ancient times, the Chinese people have used Aspergillus oryzae in the air to produce fermented soybean paste and chili sauce. Currently, chili sauce production uses Aspergillus oryzae for koji making. This strain belongs to the Aspergillus flavus group but does not produce toxins. This strain is suitable for solid-state koji making, produces protease with high activity, and also features rapid growth, easy management, relatively extensive processing, and stable total nitrogen utilization of raw materials. However, single-strain koji making has disadvantages such as incomplete enzyme systems, weak acidic protease activity, and low total nitrogen utilization of raw materials. In recent years, many researchers have used mixed koji making with multiple molds to improve the quality of chili sauce condiments.

Yeast: During the fermentation of sauces, yeast activity mainly occurs in the second stage of fermentation. The action of proteases and amylases secreted by molds, as well as anaerobic and high-salt environments, promotes yeast growth. The main yeasts used in sauce brewing are Accharomyces rouxi, Saccharomyces rubrum, and Torulopsis spp. Saccharomyces rouxii possesses slight alcoholic fermentation ability, capable of producing esters, succinic acid, and furfuryl alcohol (one of the flavor components of sauces), thus enhancing the flavor of sauces. Yeasts combined with sauce mash fermentation are mostly present near maturity and can undergo alcoholic fermentation, imparting a unique flavor to the sauce.

Bacteria and Lactic Acid Bacteria
In sauce production, bacterial metabolites can be used to improve the flavor. For example, during fermentation, lactic acid bacteria can break down glucose into organic acids such as lactic acid. They can grow in high-salt environments and esterify with alcohols produced by yeast to form esters, such as ethyl lactate, contributing to the sauce's distinctive flavor. Furthermore, in the development of some low-salt foods, organic acids and lactobacillus produced by lactic acid bacteria metabolism are often used to inhibit the growth of spoilage bacteria, thereby reducing the amount of salt used.