Chapter 1: Losses and wastes in the food chain • 1

Chapter 1

Losses and wastesin the food chain

1.0 Overview food losses andfood wastes in developingcountries

A great proportion of food produced indeveloping countries is lost throughbiological, physical and chemicaldamage. These are countries which aremostly in the tropics, where conditionsare ideal for microbial and insect pests to develop. Food producers,processors, retailers and organizationsin developing countries increasinglyhave to consider reducing food lossesand wastes in the food chain as anessential prerequisite for commercialsurvival. Consumers are also becomingmore aware of the importance ofhygiene and the safety and quality offood products, thus compelling small-and medium-scale food producers,processors and retailers to maintain thehighest possible standards commiseratewith their food handling methods.Large food companies, for example,may allocate a significant proportion oftheir budget on building andmaintaining good storage facilities toreduce food losses and wastes as partof normal investment. Further, thecompany may take pride in advertisingthat they only produce or supply thehighest quality products because ofsuperior post-harvest and handlingprocedures adopted by the company.The same opportunities may not beavailable for the small-scale enterprise.Many small and medium sized foodcompanies do not have easy access toaffordable sources of information thatwill help them to identify the main

reasons and agents responsible forfood losses and wastes. In most parts ofthe world, it is rural communities thatare responsible for the production,processing and sale of foods and otherraw agricultural materials, and thiscomprises their main source of income.Four broad areas of activity areinvolved; 1. Maintaining on-farm andpost-harvest storage; 2. Transportingproduce either for sale in bulk or forretail at local markets; 3. Additionalprocessing for sale of goods in smallshops and stores or 4. Exporting.Whatever the activity and whatever thefinal outcome or market, there areissues of waste and losses involvedwherever foods and/or raw materialsare handled without adequate care.Farmers lose a large proportion of theirproduce in the field before and duringharvest and do not always get goodreturns for their time and efforts. Theproduce can be attacked in the fieldand in storage by moulds and bacteria,insects, rodents, birds other pests and,importantly, from theft and pilfering.For example, when cereals andlegumes reach physiological maturity,the grains contain too high a moisturecontent and remain soft to the feel. Inthis stage they cannot be threshedsatisfactorily without damage resulting,and this provides opportunities formould and/or insect attack. Mostfarmers leave their crop to dry naturallyin the field for several weeks aftermaturity and prior to harvest, unlessimmediate land preparation is neededfor the next crop or unless rain may be

threatening. During this dry-downperiod, losses in quantity and qualitycan be caused by moulds, bacteria,pests, birds or the weather - withconsiderable financial implicationsinvolved.Farmers or retailers who take producein bulk to market may also sufferfinancial losses because of spoilagetaking place either during long distancetransport or as the result of roughhandling. Those who produceprocessed foods for sale are faced withever greater competition from othercommercial producers. There iscompetition to produce safe and highquality foods, which can only comefrom the use of high quality rawmaterials. Substantial losses can occurdue to the rejection of processedproducts because they do not meetlocal food laws regarding safety andquality assurance.Industrial by-products from foodproduction and the processing residuesand wastes can pose a financial burdenon the urban municipality. There isneed to dispose of wastes in a mannerthat is environmentally acceptable,particularly in countries where thereare only limited industrial wastedisposal regulations. Industrial solidwastes such as orange peel, coconuthusk, fish heads, etc. or liquid wastessuch as chemicals, fish residues, oils,etc. present a particular challenge ifthey are not disposed of with care.Discharge into a pit and/or into aconvenient waterway can have bothgrave environmental effects andadverse health consequences on localcommunities.Reduction of losses and wastes in thefood chain is of enormous importancefor producers, processors and retailersin developing countries. It can providea means of improving income throughpost-harvest food processing, or byadding value to by-products by usingthe residues available for eithergenerating power (for example, by

incinerating biomass) or for theproduction of fertiliser or feed. Rice,corn and coconut husks, cane bagasse,palm kernel and spent grains, forexample, are by-products that burneasily and - when plentiful - are usefulfor the co-generation of electricity.Cassava waste or rice straw is a goodmedium for mushroom production.Foods and vegetable wastes fromprocessing can provide a basis for snailfarming or vermiculture. However, theprime objective of any food enterpriseis to maintain high standards of foodproduction, and to sell foods that meetlocal standards for hygiene, taste,presentation, etc. and for whichpremium prices may apply. To reducelosses and wastes in the food chain, itis important to fully understand theagents that cause food losses andwastes and how to prevent or minimisethem.

1.1 Importance of preventing food loss

Prevention of food losses is of vitalconcern to small and medium-scaleproducers in ACP (African, Caribbeanand Pacific) countries, and variousmeasures must be introduced at allstages between the grower and theconsumer in order to reduce wastes, toimprove food security, to generateincome and to maintain (or improveupon) profits. Food loss and wastethrough spoilage begins as soon as theplants are harvested or the animals areslaughtered. This can involve changesin flavour, loss of colour or texture,drying out, shrivelling, rotting andsimilar degradation. The basic objectiveof food loss prevention is to create theappropriate environmental conditionswhich provide sufficient protection tothe product to maintain its quality andits quantity, thus reducing both productloss and financial loss.

1.1.1 Loss in quantityLoss in quantity shows up in loss of

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weight due to food being eaten byinsects, rodents or birds or from dryingout of the product (i.e. loss ofmoisture). For example, a farmer couldlose 50% of his rice crop if bird scaringis not initiated early enough in thegrowing season. It follows that eventhough the field of grain may seem fine- a bumper crop because of thenumber of standing stalks – the realitymay be different once the harvest is underway because of birddamage/loss. In store a maize crop canbe seriously damaged by weevilinfestation – with the many kernelshollowed out. It may be that thevolume of grain in store will remain (orappear to remain) much the same, butthe losses become apparent themoment the crop is weighed. Birds andinsects are a considerable nuisance tofood crops in the field, but can also bedetrimental to the quantity and qualityof materials that are held in store.

1.1.2 Quality related lossesThese losses are typically in the form ofnutritional and chemical losses andarise largely from contamination withtoxic moulds or foreign matter. Pestscan selectively eat part of the food stuff(such as the nutritious germ of thegrain or the interior of dried fish) andreduce the value of the food as awhole. This can also affect germinationof seed with insect infestation resultingin seeds that have had their kernelcompletely eaten and/or damaged. Theissue can be important for the viabilityof genebanks where seed is kept as arepository for breeding and/or securitypurposes. Herein may be loss ofirreplaceable germplasm and reducedgene proliferation. Viable seed grainsfor planting come from good handlingand storage of high quality seeds thathave been harvested and cleaned with care.

Other examples of loss include fooddegradation, for example, with the loss

of vitamins through the adverse actionof sunlight and temperature. Somecomponents of food including fats andvitamins are susceptible to losses whenexposed to light. The breakdown ofthese components leads to unpleasantflavours and eventually spoilage, aswell as loss of nutritional value. Inmany developing countries fruits andvegetables containing vitamins such asvitamin C and riboflavin (one of the Bvitamins) are susceptible to heatdamage, which may result simply fromdisplaying them on trays and tablesexposed to the sun. Food stuffs of thiskind may be exposed to the sun frommorning to dusk, and until a customerbuys it – with little understanding ofthe degradation that has taken place.Nutritional losses occur relativelyslowly during this period, and will not be apparent to either buyer orseller (and can only be demonstrated ifan expensive nutritional analyses is undertaken). This is not alwayspractical and it is little wonder thereare few law enforcement agencies indeveloping countries that are able tomonitor the effect of sunlight on thequality of food displayed on a typicalmarket stall.The exposure of high fat foods such aspalm fruits, coconut, groundnuts,cooked and/or fried foods, etc. toexcess sunlight can accelerate chemicalchange through the development ofrancidity. This is an off-flavour whichthe pallet or the nose is quick toidentify - and highly unattractive.Rancidity makes the food inedible and unfit for human consumption.Although rancid oils such as palm oilcan be used in soap making this is nottypical of developing countries wheremost companies will simply continueto offer the spoiled foods for sale in thehope that a lower price will shift theproduct. Earnings from soap makingare not normally sufficient and, in anycase, there are few instances wherefood inspectors can be found chasing

these retailers; offering oils as foods isan easier option. Soap making fromrancid oils increases the cost of thesoap, because more caustic soda isrequired for the saponification processdue to the presence of high levels offree fatty acids. Most soap producerswould pay less for oil that has >20%rancidity, with the likelihood ofrejection for oils of >60% rancidity.

With few exceptions, yeasts andbacteria are undesirable in the foodchain. Some moulds, for example,Aspergillus flavus produce toxins oneof which is aflatoxin. Aflatoxin-producing moulds can grow on manyproducts but maize, groundnuts andcoconuts are particularly susceptible toattack. These toxins pose long termhealth hazards and it is in the interestof the grower, producer and theconsumer to reduce food losses as aconsequence of this toxin-producingmould. Some types of bacteria andviruses are potentially highlydangerous, and efforts should be madethrough good food storage andhandling by processors to ensure thattheir products are not contaminated.Vegetables and meat which have lowacid contents are more prone tobacterial damage, and thus have thehighest risk of causing food poisoning.Prevention of loss is an excellentmeans of producing good quality foodswhich pose no health risks to people.

Another objective of food lossprevention is to reduce the level ofcontamination with wastes from insectsand other vermin such as larvae,fragments, hair, excreta and urine aswell as dust and other materials thatenter the product through mishandlingand/or contamination For example, alarge proportion of locally-producedrice cannot always be sold atcompetitive prices compared to thosefrom commercial rice growers (orimporters) because of the amount of

stones, soil, tare and similar found inthe samples offered for sale. Most localfarmers do not have access to theequipment required for cleaning thegrain prior to sale.

Food loss prevention is more relevantin developing countries than elsewherebecause of the small-scale nature ofproduction, and the use of traditionalor improved farming and post-harvesttechnologies involved. A furtherconstraint is the harsh climaticconditions that prevail in manycountries, which affect level ofproduction. If farmers are to gainfinancially from their efforts andlabour, then they must prevent foodlosses and minimise food wastethrough good quality management.

1.2 Importance of food wasteminimisation and management

Food waste minimisation is asimportant as food loss preventionbecause >80% of marketable foodsurpluses are left to waste either on thefarm or in the markets, if not soldwithin a few days (sometimes at giveaway prices) or processed into valueadded products. These food wastescreate a financial burden to the grower,producer or consumer but can also bea considerable environmental hazard.Large amounts of rotten fruits andvegetables are often dumpedhaphazardly in markets or in pits withno further treatment and thisencourages flies, vermin and/or badodours. Small-scale food processorsnormally do not have adequate wastedisposal facilities on-hand, and oftendump food wastes in much the samemanner that they would dump foodwastes from the home. The volumesinvolved, however, can be verydifferent with additional stress placedon the municipal waste dump and/orlarge quantities of liquid wastesreleased into drains and rivers. This cancause severe environmental pollution.

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Recycling and re-use of materials,waste minimisation at source andintegrated pollution control areimportant factors to consider in thedesign and operation of amanufacturing plant. Legislation toprevent this kind of environmentalissue is typical of the industrialcountries, but is only just becoming thesubject of legislation in the ACPcountries.

Depending on individual processes,varying amounts of waste materials areproduced – from a host of materialsand/or sources. Plant waste, forexample typical of a fermentationplant, may include unconsumedinorganic and organic mediacomponents, microbial cells and othersuspended solids, waste water fromcleaning operations, cooling water, andwater containing traces of solvents,acids, alkali and similar materials. Acheap and simple means of disposingof wastes of this kind in the ACPcountries would, typically, bedischarge directly to a convenient areaof land or into a nearby water course.(This supposes that the ACP countrydoes not have adequate environmentalprotection legislation or, equallytypical, this legislation is not enforced).Although most fermentation effluentdoes not contain toxic materials whichdirectly affect aquatic flora or fauna inthe discharge stream when in smalldoses, it is essential to abandon suchpractices. Unfortunately, these non-toxic effluents do contain high levels oforganic matter which is readilyoxidised by microbial attack, and thiswill drastically deplete the dissolvedoxygen content in the receiving water -unless there is a large dilution factorinvolved. This can have a disastrouseffect on the ecology of the watercourse where, for example, peopledownstream may depend upon it foraccess to fish (as a source of foodprotein), drinking water, washing, etc.

Different aquatic species such as fish,shrimps, oysters and other shell fishhave varying degrees of tolerance todepleted oxygen levels and, as aconsequence, some species will die offin specific stretches of the receivingwater depending on the levels ofdischarge. In other regions of the river,different populations capable oftolerating lower oxygen levels willsurvive. This indiscriminate disposal ofwaste into water bodies will eventuallyaffect the nutritional and livingstandard of the entire catchmentpopulation and, particularly, those whorely upon water in the river for theireconomic livelihood.

It is important to dispose of processedwastes in a judicious manner.Obviously the introduction of a ‘goodhouse keeping’ regime should bepromoted and encouraged by allconcerned in the community. This toinclude the municipal waste handlingcompanies, the city managers and localand central governments. There ismuch to be gained by a communityapproach. For example, pre-treatmentof the effluent to recover waste organicmaterials may provide opportunities forlivestock feed industries and/ornutrient products that can be used as asoil enhancer or as a fermentationmedia. The exploitation of marketablewastes/by-products helps to offset thecost of the treatment processesinvolved. This may sound almostimpossible for the small-scale producerbut the additional investment in such aventure may create new incomestreams, and will help to protectagainst the environmental degradationthat may follow from theindustrialisation or over population ofa region. There are considerableadvantages in reducing the quantitiesof materials used and recyclingwastes/by-products whenever thisfeasible within the production process.This results in benefits for a healthy

environment. There are several ways ofminimising and managing food wastessome of which are described inChapter 8.

1.3 Importance of hygieneMaintenance of good hygiene in thefood chain is essential to reduce therisk of food contamination, food lossand waste. Food spoilage isencouraged by the creation of anunhygienic environment where micro-organisms, insects, pests and otheragents of food spoilage can thrive. It isimportant that the food producer,processor or retailer is able to identifyall potential hazards, develops apractical hygiene plan and ensures thathis/her staff are adequately trained andunderstand (and fully accept) theirrespective responsibilities. The foodproducer, processor or retailer has theresponsibility to provide a clean, safeand healthy environment in his/hercommunity by respecting the followingissues.

1. Weeding around the farm to reduceopportunities for rodents, etc. to survive. Rodent infestation can result in massive on-farm losses (Fig. 1).

2. Keeping buildings and equipment clean at all times (Fig. 2). Workers must be trained to keep equipment and space in food processing factories thoroughly clean, and to remove waste from the building as it accumulates. The frequency and type of cleaning will depend on the food being processed. For example, in dry processing or processes that use dry powders such as flour, it is essential that all dust is cleaned from the building including windows, ledges,discarded sacks, etc. that are frequently over-looked. The objectiveis one of preventing any area fromcollecting dust that will provideopportunities for insects to breed.

For wet processes, cleaning must bedone with the use of detergents andsterilants. Detergents remove foodresidues, but do not kill micro-organisms. Sterilants (such as chlorine)kill micro-organisms, but do notremove food residues. A good cleaningregime requires the use of bothdetergents and sterilants. Consider:1. Training workers to understand the

importance of good hygiene, for example, workers must always wash their hands with soap and clean water after using the toilets. It follows that these facilities have to be provided to workers.

2. Preventing smoking or spitting in stores or processing areas.

3. Workers who are ill should not be permitted to handle foods under any circumstances. This is especiallyimportant for those suffering from diarrhoea or skin infection – people who remain highly infectious. Sick workers should be sent home.

4. Workers with cuts, boils or abrasions on their hands, etc. should be restricted from working within food handling and/or preparing areas; and assigning duties elsewhere in the plant or farm.

5. Advising households on the disposal of wastes in an appropriatemanner and, where available, to make use of recommended dumps. The use of waste bins with lids is recommended to reduce fly populations, which will act as agents of food contamination.

6. Maintaining a rigid cleaning schedule which should be seen as an integral part of the overall ‘good working practices’ adopted within the plant.

1.4 Purpose of this bookThe Food and Agricultural Organisationof the United Nations (FAO) is aleading international source of high

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Figure 1.1 Weeding around the farm helps to reduce rodent attacks.

Figure 1.2 Keep buildings and equipment clean at all times.

quality information concerned withfood production and processing. FAOis frequently requested to provideadvice on how to reduce food lossesduring production, processing,transport and storage and how tominimise food waste in the food chain.There is a wealth of informationavailable but much of it is dispersedand, further, prepared in such a waythat it can be difficult for the small-scale food producer to understand.People in small-scale industries areoften unable to assess the potential ofpreventing losses from production onthe farm, in food factories or whenpreparing food for consumption in thehome. This book aims to make adifference and describes, in a practicalmanner, some of the technicalinformation and guidelines required tohelp producers, processors, traders andothers to reduce food losses andminimise wastes. The aim of the text isto help people to:1. Reduce loses and wastes on the

farm before harvest and during harvest.

2. Prepare an effective post-harvest management system to reduce waste and to boost returns on investments.

3. Construct and manage appropriate storage facilities for grains and legumes, fruits and vegetables, fish and meat and processed foods to ensure that these foods are handled and transported to the consumer with minimum loss in quantity and quality.

4. Deliver guaranteed high quality raw materials to food processors and retailers that they are provided with the best quality raw materials for their respective factories and shops.

5. Recycle food residues and wastes into secondary industries to enable these wastes to be used as a source of additional income and/or to protect the environment.

6. Acquire technologies for food loss reduction and waste minimisation.

1.5 Readership targetThis book is intended to assist peopleworking in a number of inter-relatedfields. This may include:1. Agricultural producers2. Agro-industrial processors3. Agro-food suppliers4. Market traders5. Factory operators6. Shop-keepers7. City managers and engineers.8. Development workers and NGOs

who work with small- to medium-scale enterprises, food producers, processors and retailers.

9. Policy makers in the public sector.10. Students of agriculture and food

science and engineering technologies who may wish to learn more about minimisation and revention of food wastes, and the possible uses of the many by-products available.

1.6 Scope of this bookThis book explores issues concernedwith losses and wastes in the foodchain from the producer to theconsumer. It aims to provide a broadoverview with messages and guidelinesfor producers, processors andorganizations working in developingcountries on how to reduce losses andwastes in the food chain. Chapter 1gives an overview of the amount of food that is lost or wasted in developing countries throughinappropriate post-harvest managementpractices, and provides the rationalbehind the need to prevent food lossand to minimise food waste. Thechapter also explores reasons why it isimportant to maintain good hygieneduring food processing and at everysubsequent level in the food chain.

After briefly considering the importanceof food loss prevention and waste

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management, the book examines thebasic principles involved with on-farmpre-harvest, harvest and post-harvestfood loss prevention and wasteminimisation. Chapter 2 looks atvarious foods such as cereals andlegumes, roots and tubers, fruits andvegetables, fish and meat and spices. Itprovides information on the agentscausing food spoilage and damage,and suggests some practical ways ofprevention during the pre-harvestperiod and when harvesting.

Transporting food to trading centressuch as markets, shops or factories cancreate food losses especially wheninappropriate packaging materials andmodes of transport are used. Chapter 3clearly shows how these can beavoided to reduce losses and minimisewaste. While considerable losses canoccur before and during harvest andtransport, the greatest losses usuallyoccur during storage. Good storagefacilities off-farm are essential to ensurehousehold and community foodsecurity through to the next harvest.Good storage also helps farmers orretailers to hold back the sale of goodsduring times of glut and to sell them atthe right time and at the right price.Chapter 4 explores crucial food lossesresulting from quality and quantity-related losses, and describes the mainagents and environmental conditionsthat create food losses in storage.Practical examples of food lossprevention are provided for the fivemain food groups - cereals andlegumes, roots and tubers, fruits andvegetables, meat and fish and dairyproducts, and processed foods.

It is important for food processors tounderstand the natural attributes of rawfood and the final quality required ofthe finished product in order to avoidwaste in the manufacturing process.Chapter 5 describes ways of preventingwaste in food industries which may

occur as a result of negligence andover-purchase of raw materials -particularly perishables such asoranges, fruits, vegetables, fish andmeat, etc. The key advice for wasteminimisation in industry is to put intoplace good production planning andinnovative marketing strategies toavoid losses due to over-stocking orover-production. It is also essential tohave some understanding of the levelof losses that can result within the fivemain food groups. Chapters 6 and 7provide some additional advice onhow to transport, store raw and/orprocessed food at wholesale and retailmarket levels and in shops. Thesechapters emphasise the ‘DOS’ and‘DONTS’ of the industry and followfrom technical advice contained in theproceeding chapters.

The accumulation of wastes from rawand, processed residues is inevitableduring food production or processing,and it is essential to consider addingvalue to these materials either byprocessing them further or using themfor other purposes such as energyproduction. Chapter 8 looks at ways ofutilising food industrial wastes insecondary industries (such as energygeneration and/or fertiliser, mushroomor snail production). Further processingof industrial wastes generatesadditional income and helps to protectthe environment (for example, withminimising the ‘greenhouse’ effectfrom discharge of carbon dioxide to theatmosphere). The technologies that canbe used in some of these industries arealso described. The annex provides acase study of how some companies,agencies and entrepreneurs have beenable to reduce food losses andminimise wastes in the food chain byusing the information available andtaking advantage of appropriateresources available from technicalinstitutions in their respectivecommunities.

Each of the eight chapters describes thelosses and wastes typical of the mainfive food groups, the constraintsinvolved and how taking action toprevent losses comes from anunderstanding of some of the manyprinciples involved.

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