Fusarium Species on Barley Malt: Is Visual Assessment an Appropriate Tool for Detection?

Abstract

Cereal Chem. 94(4):659-669Fusarium infections in malting barley cause mycotoxin contamination, quality impairment, and processing difficulties. The visual assessment of barley malt is a commonly applied practice in the malting and brewing industry to screen cereal batches for fungal infection, because it assumes a direct connection between occurring symptomatology and actual fungal contamination. The exceedance of a defined limit of red kernels (usually five to seven) in a 200 g subsample of malt is associated with an unjustifiable risk for further processing and can lead to reductions in price or the rejection of the entire batch. The present study evaluated the suitability of this method to ensure product quality and safety. It was further intended to resolve the presumed linkage between kernel discoloration and Fusarium infection. In general, symptomatology showed low predictability for Fusarium contamination. However, significant correlations became apparent between the number of discolored kernels and fungal DNA contents under conditions of higher levels of infection, although this was not the case for mycotoxin levels. Although symptomatology is likely overinterpreted in regard to its reliability as an indicator for Fusarium contaminations, it might still assist in assessing the risk of certain fungal contaminants. † Corresponding

Enzymes from Cereal and Fusarium Metabolism Involved in the Malting Process – A Review

“…affecting the malt quality mainly are reported to be F. culmorum, F. graminearum and not to be forgotten F. avenaceum and F. tricinctum. [1,51] Here some positive and negative effects are reported. Positive attributed effects include amongst others the production of hydrolytic acting enzymes contributing to the modification of malt: amylases, proteases, β-glucanases and xylanases.…”

“…are known. [1,2] The Fusarium spp. affecting the malt quality mainly are reported to be F. culmorum, F. graminearum and not to be forgotten F. avenaceum and F. tricinctum.…”

“…The term "quality characteristics" can be divided into three groups: food safety, processing quality, and product quality. [1] Food safety is mainly aimed at whether a product is saleable and implies, among other things, an absence of toxins or toxic metabolites in the product. [2] Processing quality can be impacted or influenced based on agricultural factors during plant growth or processing factors during malt and beer production since there are typically adequate amylolytic activities in the malt produced.…”

“…Similarly most malts typically have well balanced cytolytic and proteolytic enzyme levels. [1] Processing quality merges into product quality, which implies quality factors such as the germinative energy of barley, the water or protein content of barley or malt, as well as visible discoloration that indicates weathering. [2] The minimum specifications of barley product quality for malting purposes are: a sufficient germinative energy higher than 95%, [3,4] a protein content ranging from 9.5-11.5% dry basis, [4,5] a moisture of ≥14.5%, [4,6] and as few microbiological contaminants as possible.…”

“…[2] The minimum specifications of barley product quality for malting purposes are: a sufficient germinative energy higher than 95%, [3,4] a protein content ranging from 9.5-11.5% dry basis, [4,5] a moisture of ≥14.5%, [4,6] and as few microbiological contaminants as possible. [1,7]…”