Reducing microbial contamination in wheat is desirable to ensure consumer safety. In this study, the efficacy of adding organic acids and NaCl to tempering water to reduce microbial contamination in hard wheat was evaluated. Hard red winter wheat was tempered to 15.5% moisture by adding sterile distilled water (control) or tempering solutions containing organic acids (acetic, citric, lactic, or propionic; 1.0, 2.5, or 5.0 v/v), NaCl (26 or 52% w/v), or a combination of organic acid (acetic or lactic; 2.5 and 5.0% v/v) and NaCl (26 or 52% w/v). After tempering, the microbial load was significantly reduced by all the acid and NaCl treatments when compared with the control. Wheat tempered with 5% acetic, propionic, and lactic acids resulted in reductions of 1.7, 2.3, and 3.8 log colony forming units (CFU) per gram in aerobic plate count (APC), Enterobacteriaceae (Eb), and mold counts, respectively. The combination lactic acid (5.0%) and NaCl (52%) was the most effective against APC and Eb, with an average reduction of 4.3 and 4.7 log CFU/g, respectively. Tempering wheat with organic acids and saline solutions may provide milled products with improved microbiological quality when compared with the traditional tempering process using water.

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Cereal Chem. 94(3):502-507Previously, we showed that tempering with saline organic acid solutions can reduce the aerobic plate count of wheat by as much as 4.3 log CFU/g. The purpose of this study was to evaluate the impact of these tempering solutions on the functional properties of resulting whole grain (WGF) and straight-grade (SGF) flours. Wheat was tempered to 15.5% moisture by tempering with sterile distilled water (control) or solutions containing NaCl (26% [w/v]) together with organic acid (acetic or lactic 2.5 and 5.0% [v/v]). After milling, fractions were collected and recombined as needed to obtain WGF or SGF. The acid content in WGF was higher than in SGF, indicating limited penetration of the organic acids into the endosperm of the grain. In WGF, the saline organic acid treatments caused a decrease in paste viscosity and bread crumb cell sizes in breads. In SGF, the saline organic acid treatments caused significant changes in paste viscosity and some Mixograph parameters; however, principal components analysis indicated that the treatments did not substantially affect SGF functionality. Thus, WGF was altered by the saline organic acid solutions, whereas SGF functionality was minimally affected by tempering treatments, perhaps because of acids only partially penetrating into the endosperm. † Corresponding author. Phone z Mean ± standard deviation (n = 3). AA = acetic acid; LA = lactic acid; and percentage values denote concentration. Means followed by different letters within row are significantly different (P < 0.05).

Maize ( Zea mays) is a staple in many developing countries but is known to be prone to pest (insects, birds, and rodents) and fungal infestation. In Guatemala, mycotoxin contamination of cultivated products may occur owing to such factors as environmental conditions and the use of traditional agriculture operations. To assess the current maize conditions in Guatemala, a small-scale study was performed. Mold and insect counts and mycotoxin (aflatoxin and fumonisin) concentrations were determined on 25 farms in two townships (Chiantla and Todos Santos) of the Huehuetenango Department. Total fungal counts were 3.6 to 6.83 log CFU/g with no significant differences ( P > 0.05) across farms at different altitudes. Farms where maize was not produced but was purchased were at higher risk of fumonisin contamination, whereas local producers were mostly affected by aflatoxins. Aflatoxin was present in maize from 100% of farms at 1.0 to 85.3 ppb, and fumonisin was detected on 52% of farms at 0.4 to 31.0 ppm. Average mycotoxin consumption amounts were above the recommended maximum intake for aflatoxin in both produced and purchased maize and above the provisional maximum tolerable daily intake for fumonisin in purchased maize. Estimated daily intake was 0.01 to 0.85 μg/kg of body weight per day for aflatoxin and 2.9 to 310.0 μg/kg of body weight per day for fumonisin. An entomological analysis revealed overall 32% prevalence of Ephestia kuehniella (flour moth), 16% prevalence of Sitophilus zeamais (maize weevil), and 8% prevalence of Tribolium sp. (flour beetle) on the analyzed farms. This study highlighted poor agricultural practices used in the highlands of Guatemala. Current practices should be revised for the production of maize that is safe for consumption by the population in this region.

Cereal Chem. 93(2):105-115Throughout history, wheat-based foods have been considered among the safest of all foods produced for human consumption. In part, this claim reflects both the low risk profile of low-moisture foods and the thermal processes used to produce the finished product. Nevertheless, raw flour contains a number of potential hazards, which, if not properly managed, may have the potential to result in serious public health consequences. These hazards are mostly microbiological in origin and arise mainly during production and distribution through the wheat supply chain. The physical processes carried out during milling have minimal impact on the level of contamination present on grain; therefore, the initial microbiological quality of wheat grain has a strong influence on the ultimate quality and safety of milling end products. Although most flourbased foods are processed and consumed in forms that are less likely to be contaminated with pathogens, refrigerated dough products have the potential to be a safety hazard to consumer health because they could be consumed raw or undercooked. The risk for exposure to pathogenic microorganisms present in raw flour by eating uncooked baking mixture has been demonstrated by several outbreaks. Such food safety incidents have led to heightened manufacturer and consumer awareness about safety related to flour-containing foods. † Corresponding . 1985.Effect of cleaning, milling, and baking on deoxynivalenol in wheat. Appl. Environ. Microbiol. 50:482-486.