Potential application of lactic acid starters in the reduction of aflatoxin contamination in fermented sorghum-millet beverages

Abstract

Background: Aflatoxin contamination in traditionally fermented cereal-based beverages is a serious food safety challenge considering that commercialization of these products is rising. The challenge is aggravated by the fact that aflatoxin elimination from the food chain is almost impossible. This paper focuses on Obushera, a popular traditional spontaneously fermented sorghummillet beverage from Uganda. Method: Mold and total aflatoxin levels in cereal flours and Obushera from different markets in Kampala were determined. Ability of lactic acid bacteria (LAB) starters from Obushera; Lb. plantarum MNC 21, W. confusa MNC 20 and L. lactis MNC 24 to bind aflatoxin B1 (AFB1) was evaluated against Lb. rhamnosus yoba 2012 as the reference strain. Results: Mold counts in sorghum, millet and Obushera ranged between 0.0-2.4 log cfu/g, 2.0-6.5 log cfu/g and 2.0-5.5 log cfu/g, respectively. None of the flours complied with food safety standards for molds (maximum = 4 log cfu/g) while 88.0% of Obushera did (standard = maximum 1.3 log cfu/g). Total aflatoxin levels in sorghum, millet and Obushera were 22.3 ± 21.2 ppb, 9.9 ± 10.0 ppb and 10.4 ± 6.1 ppb, respectively. LAB bound 19.3-69.4% of AFB1 in a 1000 ppb solution with binding efficiency in the order of Lb. rhamnosus yoba 2012 = Lb. plantarum MNC 21 > W. confusa MNC 20 = L. lactis MNC 24. The LAB-AFB1complex remained stable under a series of washes with physiological saline. Conclusion: This study indicates that LAB with aflatoxin binding properties can be exploited for controlled cereal fermentations to improve food safety.

Aflatoxins in Uganda: an encyclopedic review of the etiology, epidemiology, detection, quantification, exposure assessment, reduction and control

“…The methods for detection of AFs in agricultural foods have been reviewed in sufficient details by some Ugandan authors [13]. This also explains, in part, the fact that most AF investigations in Uganda following this review such as that of Muzoora et al [71], Echodu et al [69], Wacoo et al 476 [73] and Byakika et al [64] employed selective and highly sensitive methods. [85] Years cited represent the year the data were published with most data collected in over 2 months to 1 year.…”

“…In Uganda, AFB1 is the most studied [62] while AFM1 have received little attention [63]. Thus, most studies reported AFB1 levels or did not distinguish between the different types [64][65][66][67][68][69]. Others, such as the validation survey of Wacoo et al [70], Muzoora et al [71], Baluka et al [72] and Wacoo et al [73] differentiated the AFs.…”

“…Mold and total AF content of cereal flours and Obushera (a local cereal based beverage) from markets in metropolitan Kampala were evaluated by Byakika et al [64]. The capacity of lactic acid bacteria (LAB) starters from obushera; L. plantarum MNC 21, Weisella confusa MNC 20 and L. lactis MNC 24 to bind AFB1 was evaluated against L. rhamnosus yoba 2012 (as a reference starter strain).…”

“…The LAB bound 19.3-69.4% of AFB1 in a 1000 μg/kg matrix, with binding efficiency in the order of L. rhamnosus yoba 626 2012 = L. plantarum MNC 21 > W. confusa MNC 20 = L. lactis MNC 24. The LAB-AFB1 complex 627 was reportedly stable to physiological saline washes, indicating that the LAB with AF-binding 628 properties can be harnessed for controlled fermentation to reduce AF content of obushera [64].…”

Aflatoxins in Uganda: An Encyclopedic Review of the Etiology, Epidemiology, Detection, Quantification, Exposure Assessment, Reduction, and Control

“…In Uganda, AFB 1 is the most studied [56] while AFM 1 has received little attention [57]. us, most studies reported AFB 1 levels or did not distinguish between the different types [58][59][60][61][62][63]. Others, such as the validation survey of Wacoo et al [64], Muzoora et al [65], Baluka et al [66], and Wacoo et al [67], differentiated the AFs.…”