The development of indigenous starter cultures for producing fermented foods that meet the expectations of Cambodians is necessary to preserve the country’s food supply. In this study, the safety of 46 lactic acid bacteria strains based on the phenotypic antibiotic susceptibility to clinically relevant antibiotics was assessed. The antibiotic susceptibility of 39 lactobacilli and seven pediococci isolated from Cambodian fermented foods to 16 antibiotics was studied according to ISO 10932/IDF 233. The results were interpreted based on the minimal inhibition concentrations obtained, using differently defined breakpoints and concentration distributions as well as data from the scientific literature. Applying only breakpoints, the results demonstrated two Lactiplantibacillus pentosus, three Companilactobacillus futsaii, three Levilactobacillus namurensis and seven Pediococcus pentosaceus strains with acquired resistance. However, considering further information, one Companilactobacillus futsaii, one Limosilactobacillus fermentum and respectively three Lactiplantibacillus pentosus and Levilactobacillus namurensis strains would possess an acquired resistance. The genetic background for the absence of transmissible antibiotic resistances in lactic acid bacteria strains intended for food application must be confirmed by molecular methods for potential starter cultures.

Naturally fermented foods are an important part of the typical diet in Cambodia. However, the food safety status of these products has not been widely studied. The aim of this study was, therefore, to provide an overview of the quality of these foods in relation to microbiology and biogenic amines. Additionally, the obtained results were compared to the habits and practices of Cambodians in handling this type of food. A total of 57 fermented foods (42 fishery and 15 vegetable products) were collected from different retail markets in the capital of Cambodia. Pathogenic Salmonella spp., Listeria spp., and Listeria monocytogenes were not detected in 25 g samples. Generally, less than 102 cfu/g of Staphylococcus aureus, Escherichia coli, Pseudomonas spp., Enterobacteriaceae, and molds were present in the fermented foods. Bacillus cereus group members (<102 to 2.3 × 104 cfu/g), lactic acid bacteria (<102 to 1.1 × 107 cfu/g), halophilic and halotolerant bacteria (<102 to 8.9 × 106 cfu/g), sulfite-reducing Clostridium spp. (<102 to 3.5 × 106 cfu/g), and yeasts (<102 to 1.1 × 106 cfu/g) were detected in this study. Still, the presence of pathogenic and spoilage microorganisms in these fermented foods was within the acceptable ranges. Putrescine, cadaverine, tyramine, and histamine were detected in 100%, 89%, 81%, and 75% of the tested products, respectively. The concentrations of histamine (>500 ppm) and tyramine (>600 ppm) were higher than the recommended maximum levels in respectively four and one of 57 fermented foods, which represents a potential health risk. The results suggest that the production process, distribution, and domestic handling of fermented foods should be re-evaluated. Further research is needed for the establishment of applicable preservation techniques in Cambodia.

Screening for various types of lactic acid bacteria (LAB) that form the biological agent γ-amino-butyric acid (GABA) is important to produce different kinds of GABA-containing fermented foods. So far, no GABA-producing LAB have been reported from Cambodian fermented foods. Most small-scale fermentations and even some industrial processes in this country still rely on indigenous LAB. The application of GABA-producing autochthonous starters would allow the production of Cambodian fermented foods with an additional nutritional value that meet the population's dietary habits and that are also more attractive for the international food market. Matrix-assisted laser desorption/ionizing time-of-flight mass spectrometry (MALDI-TOF MS) and partial 16S rDNA sequencing were used to identify 68 LAB isolates from Cambodian fermented foods. These isolates were classified and grouped with (GTG)5 rep-PCR, resulting in 50 strains. Subsequently, all strains were investigated for their ability to produce GABA by thin layer chromatography. GABA-positive strains were further analyzed by the GABase assay. Of the six GABA-positive LAB strains-one Lactobacillus futsaii, two Lactobacillus namurensis, and three Lactobacillus plantarum strains-two Lactobacillus plantarum strains produced high amounts of GABA (20.34 mM, 16.47 mM). These strains should be further investigated for their potential application as GABA-producing starter cultures in the food applications.

Food fermentation technologies have developed through years of experience rather than scientific findings. Therefore, many small-scale manufacturers are unwilling to accept changes and to modify fermentation processes. Still, traditional fermented foods have had an essential role in human nutrition for thousands of years. A wide range of diverse cereals, legumes, vegetables, fruits, fish, seafood, and meat are used as raw materials for the production of these fermented foods by back-slopping (a process where material from a previous successful batch is added to facilitate the initiation of a new batch) or naturally occurring microorganisms. Various microorganisms that influence the quality, safety, sensory properties, acceptability, and consistency of these products are present. Lactic acid bacteria with their beneficial characteristics are generally a significant contributor. Identification and profiling of microorganisms in fermented foods are of particular interest. But so far such information has not been explored in detail for some fermented products from the lower Mekong subregion. Improving the safety, quality, and acceptability of fermented foods, while reducing their production costs and maintaining their authenticity and uniqueness, is important. This can be achieved through starter culture application and greater attention to food safety, such as HACCP approaches. Recent scientific advances have led to the development of defined microbial starters, leading to the transfer of artisanal food production to more controlled and industrialized fermentation. The aim of this review is to determine the gaps in the knowledge of traditional fermented foods of the lower Mekong subregion and to present current information on the diversity of involved microorganisms. These data will be helpful for defining future strategies toward the sustainable production of safe fermented foods particularly those from southeast Asia.