Cereal foods fermented by lactic acid bacteria are staples in many countries around the world particularly in developing countries, but some aspects of the nutritional and health benefits of traditional fermented foods in developing countries have not been sufficiently investigated compared to fermented foods in high-income countries. Today, malnutrition worldwide is characterized by a double burden, excess leading to non-communicable diseases like obesity or diabetes alongside micronutrient deficiencies. In addition, populations in developing countries suffer from infectious and parasitic diseases that can jeopardize the health benefits provided by their traditional fermented foods. Using examples, we argue that research on traditional fermented cereals in developing countries should focus more on their effect on inflammation and oxidative stress under conditions including infectious or non-infectious gut inflammation.
1 March 2017 in International Journal of Food Microbiology
The objective of the present work was to estimate the prevalence of Bacillus cereus group species in traditional cereal-based lactic acid-fermented slurries and nonfermented flours used to prepare infant foods in an African context. High counts on mannitol-egg yolk-polymixin agar medium were determined for the fermented slurries (median, 4.5 × 10(4) CFU/ml of slurry) compared with the nonfermented flours, most of whose counts were lower than 10(-1) CFU/g. Virulence genes were characterized in 60 isolates from 26 traditional cereal-based foods in Ouagadougou (Burkina Faso). Seventy-two and 38 % of isolates were positive for the complete set of genes coding for hemolysin BL and nonhemolytic enterotoxin, respectively, suggesting a high enterotoxigenic potential for these foodborne isolates. No potentially emetic toxin-producing strains were detected. Because of the high counts found for fermented slurries, survival tests with vegetative cells inoculated in fermented slurries were performed, which showed that growth of B. cereus was inhibited. This result suggests that fermentation in traditional production units is presumably not adequately controlled, enabling growth during any unit operations before fermentation, or even during the fermentation step, when the process was poorly controlled. However, adding nisin (0.1 mg/ml) enabled a 5-log reduction in the B. cereus population in 5 h, suggesting that the use of nisin could be a way to upgrade the hygienic quality of this type of food.