1. Digital Re-print - May | June 2012Mould control in grain and feed preservation Grain & Feed Milling Technology is published six times a year by Perendale Publishers Ltd of the United Kingdom. All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. Copyright 2010 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1466-3872 www.gfmt.co.uk

2. FEATUREMOULD in grainand feedCONTROL preservation by Andr Meeusen, application manager and Yvonne van der Horst, technical manager,Kemira ChemSolutions b.v., The NetherlandsMoulds are ubiquitous and unavoida-a widespread application, however, this is not shelf life, maintains nutritional value, and preventsble contaminants in all animal feeds. an efficient way to tackle the problem as they formation of mycotoxins.Virtually all animal feeds containdamage the nutritional quality of feeds. Thesemoulds and viable mould spores which continue toxin binders, which usually contain different Mould and moistureto pose a threat to grain quality.types of clay minerals, are not that efficient and Development of moulds in feed depends onmay even compromise nutrient digestibility.the interaction of several factors, including theMoulds are fungi which are distinguishedMoreover, mycotoxin contaminated feeds can presence of spores, the availability of nutrients,by the formation of mycelium (a network impair the animals health and productivity duestorage time, temperature and moisture. Waterof filaments or threads), or by spore masses. to loss of appetite, feed refusal, allergic reactions, activity, i.e. the presence of free water, is theConditions that favour moulds include moisturereproductive failure, suppression of the immunemost important factor in the growth of moulds.levels higher than 12 percent, warm tempera-system and even mortality. Indeed, microbial spoilage of food and feedstures, the presence of oxygen, and prolongedContamination by moulds and consequently,occurs at different levels of moisture and thestorage time. the production of mycotoxins, can be greatly water activity (aw) concept describes the waterMany moulds are toxigenic and produce reduced by using organic acids as inhibitors.available for microbial growth.mycotoxins, a secondary metabolite created by Organic acids effectively inhibit the growth ofMost feed mills optimise or maximise mois-moulds that is toxic to organisms other than themoulds, yeast and bacteria in different types of ture levels during feed production to com-mould itself. The growth of moulds and produc-feedstuffs and prevent recontamination after pensate for losses that occur during grinding,tion of mycotoxins by these moulds in feedproduction of the compound feed. This extendspelleting and cooling processes. Moreover, aingredients can cause significant eco-sufficient moisture level reduces thenomic losses. They consume valuable energy usage during the pelletingfeed nutrients such as vitamins and process and results in better pelletamino acids and they convert energy quality. The drawback of increasinginto water and CO2 and can causemoisture levels is that increasing levelstemperature increase as a result of of free water creates ideal condi-their carbohydrate metabolism (seetions for rapid mould growth and thebelow)development of mycotoxins. MouldsC6H12O6 + 6 O2 => 6 CO2 + 6 and yeast grow at aw > 0.75 and aw >H2O + Heat0.85 respectively.Mould growth depletes the nutri- Products that protect feeds againstent density and affects feed palatabil- mould growth and at the same timeity and consequently decreases feed lower the aw are based on calciumintake. Moulds cause lipid oxidationor sodium propionate. Propionic acidand pigment deterioration and are is reacted with calcium or sodium todetrimental to animal health, perform-produce a salt with high propionic acidance and reproduction. The most level, 76-78 percent depending onfrequently found mycotoxins are afla-Fig 1: Assessing the activity of Kemira Mould Controlthe salt form. The acid is completelytoxins and ochratoxin produced by SP1 (calcium propionate) using a CO2 test on mash buffered, has a good solubility, is safeAspergillus, the latter are also produced feed. (Kemira ChemSolutions, Tiel, The Netherlands).to use and easy to handle. Theirby Penicillium and zearalenone andefficiency in shelf life extension whentrichothecenes produced by Fusarium used in feeds is dose related and canmoulds. be easily demonstrated by an in vitroaccelerated method, increasing mois-Toxin binders vs. organic ture content and storage temperature,acids by measuring the CO2 productionAnimal feed is susceptible to mould over time. An efficient preservativegrowth. The microbiological quality ofeffect is obtained up to the momentfeed is a comparatively unexploredthat CO2 production starts to increasearea but is receiving more attention(Figure 1).due to the recognition of mycotoxinsas a widespread economic threat. Fig 2: Aspergillus niger growth inhibition efficaciesGrain preservationof organic acids on ground whole wheat grains.The use of toxin binders in feed isAnimal feeds generally contain18 | may - June 2012Grain&feed millinG technoloGy 3. Siwertell grain ship unloader at Rizhao Port, ChinaGrain handling systemsthat you can truly rely onCargotecs land-based Siwertell ship unloaders and loaders are designed to suit each terminals specificrequirements. Siwertell systems use unique enclosed screw conveyor technology to ensure that dry bulk cargooperations are environment-friendly and efficient.Let the dry bulk handling experts design a custom-made answer to your particular needs.www.cargotec.com www.siwertell.comSIWERTELL IS A CARGOTEC BRAND 4. FEATUREof propionic acid Finland and compared to ammonium buff-Table 1: Mould inhibiting and killing-off effect of Propionic acid (KemiraMould Control LP1) and formic propionic (Kemira Mould Control LF1)to overcome the ered propionic acid (Kemira Mould Controlbuffered products in highly challenged conditions (Wessling 2011) odour and corro-LP1 NC). Figure 2 shows that the initialsion problems.inoculation with Aspergillus niger in grainsTREATMENTSRESULTS To enter into without preservatives resulted in significant0.day 7.day14.day the mould cell, the growth during the first week. Both KemiraName%Mould cfu/gMould cfu/g Mould cfu/g acids have to pass aMould Control LP1 NC and Kemira Moulddouble barrier, the Control LF1 at 0.2 w/w-%, inhibited growthPositive control: ASPERGILLUS inoculated 3.51044.7105 2.0107 cell membrane and of Aspergillus niger in grinded whole wheatthe outer cell wall ofgrains over a 2 weeks period and total killKemira Mould Control LP1 nc 0,41.0103