The Sources, Effects and prevention measures of Fungal Toxins to agricultural crops.

Welcome to the series of Post harvesting Technology.

Today I'm going to share with you the sources, effects, and  prevention measures that should be taken to prevent  Fungal toxins to agricultural crops i.e grains after harvesting.

 Now days Farmers across the world  are facing the huge problem of Fungal toxins  to their harvested crops, that makes them failing to maintain long term storage and even leads to cause diseases like Cancer, and diarrhoea after consumption of  foods that have been  affected by those Toxins.

Examples of Maize that have affected by  Fungal Toxins i.e Aflatoxins.

Below are groundnuts that have been affected with Fungal Toxins.

Following are the sources of Fungal Toxins to agricultural crops. 

The Fungal toxins are normally  attacking  many food crops like grains, root crops i.e Cassava, ground nuts, eggs, meat,and  Milk from animals. They  are originated from the soil dusts ( Inactive spores) and get attacking the kernels of grain slowly untill they affect at larger portions.  Also they can be found from the farm residue of decayed organic matters. They prefers mostly to grow in wet and hot condition and  can  attack  agricultural crops  during the production period of crops, harvesting, drying, dehuling, dehusking, winnowing, sorting, grading,  transportation, and even during storage. 

The Fungal toxins can occur in many forms; for example the toxins which normally  affect  Maize grains are; Aflatoxins, Ochratoxins, and Fumonisins. 

The Fungal Toxins are not seen by our naked eyes, they have not any smells, colour, and even flavour. But the Fungus that causing those Toxins are seen to be of different colours like green, oranges, dirty Yellowish,and even grayish colour. The Fungal Toxins can be only seen from the Laboratory diagnosis. 

Types of Fungus and their respective Toxins.                   

1. Aspergillus Species  (A.Flavus and A. Parasiticus). They cause Aflatoxins B1, B2, G1, G2)

2. Penicillium and Aspergillus spp.

They cause Ochratoxins( A, B C)

3. Fusarium Spp. 

They cause Fumonisins B1, and B2.

ENVIRONMENTAL CONDITIONS THAT FAVOUR THE GROWTH OF FUNGI AND FORMATION OF FUNGAL  TOXINS.

>The primary source that accelerates growth of fungi na formation of Fungal Toxins to the agricultural crops includes wetness, and hotness if the crops has been faced with environmental stresses like drought.

>The growth of Fungi and formation of Fungal Toxins are happening very rapidly and spreaded at large during extreme hot condition, or extreme wet condition. The high temperature of about 32-38°C, and moisture contents of 80-85% tends to accelerates the growth of fungi causing Toxins.

SIDE EFFECTS OF FUNGAL TOXINS TO HUMAN HEALTH, LIVESTOCK FARMING, AND NATIONAL  ECONOMIC.

  • short term side effects to human being.

If human will eat foods that have been affected by those toxins it can leads to death, damage of Liver, vomiting, diarrhoea, fever, Jaundice, swelling of stomach, and legs.

  • short term side effects to livestock Farming.

   > Liver failure and damage. 

>Animal or poutry shaking and falling down, leakage and decay of teeth for animals.

•Long term side effects to human

> Cancer of Liver, throat, and kidney.

>Depletion of body immunity

>Reproductive problems to both men and women.

>Failure of Kidney functioning 

>Failure of both heart and nervous system and finally death.

>Children Stunting of growth to both brain and body.

•Long term side effects to livestocks

>Stunting in growth. 

> Decreasing production of meat quality, Eggs and milk yield.

> Decreasing of the Livestock Immunity system.

• Economic side effects of Fungal Toxins to national wide.

>Decreasing of man power within the country due to death incidences.

>Increasing of Hungry disaster due to lack of  both quantity and quality foods.

>Decreasing of agricultural yield production.

>Decreasing of the quality of agricultural crops that leads to affecting both national and international marketing.

STRATEGIES  UNDERTAKEN TO PREVENT FUNGAL TOXINS TO AGRICULTURAL CROPS.

The strategies have been divided into 2 categories.

1. Pre harvesting Strategies.

>It has been investigated that, the Fungal Toxins are started from the farm before harvesting untill the storage stage. Hence prevention during the farm stage is very crucial to avoid further spreading at the post harvesting stages.

>Different methods have been scientifically approved to fight and reduce Fungal Toxins to grains like Maize.

Chemical usage, Proper agricultural practices, and Biological methods.

> Biological methods has proved to show great results to fight for  toxins at the different places in the world by using safe fungi known as Aflasafe.

> Ten kilograms of Aflasafe are used in one hecre and then spreaded to the farm two weeks before plant starts to generates flowers.

>Another strategy is to conduct a research of modified seeds that are strongly resistant to fungi which causing Toxins.

2. Post harvesting Strategies.

Post harvesting staregies should be supervised inorder to have proper storage environment so as to resist pests and fungi attack.

>All grains and other crops should be harvested soonly  after have been matured.

>The grains should be sorted well to separate from those which has infected by pests or fungi.

> Once grains have been harvested,  they should be dried well untill it reaches the recommended moisture content. This  should be done through  an elevated and cleaned structures, or on the top of canvas.

> The harvested grains should be stored in the clean area, cool and dry condition.

> The stacks Carried grains are supposed to  be placed on top of an elevated structure to prevent entering of dusts .

> All stacks should strongly resistant to attacking  pests.

Thanks you for your cooperation, those were the few explanations on how Fungi toxins are originated, effects,. and how to prevent them effectively.

The next topic will be Grain Storage and handling for better and long term consumption to consumers.

How to improve Quality Assurance of Milk.

Many farmers faces challenges of maintaining the quality of milk before and after milking from the animals like cow.

But here we will see how to maintain the quality of milk before milking, and after milking.

01. Maintaining the milk quality before delivered from the animal.

>Lactating animals should be of good health free from diseases causing decrease in milk quality like Mastitis, and should be washed before milking.

>Animal should be regurally provided good nutritional  food content  that boost milk production. Foods having enough of calories, Fats, Proteins, Fibres, and minerals are required to make sure the milk produced is of high quality.

> The Farm Field should be normally clean enough to prevent animals from diseases attack.

02. Maintaining  milk quality during Milking from the animal.

>The milk containers should be washed with portable water and soap and dried before milk is poured into it. This will reduce contamination with Exogenous  agents.

>Operator who milking the animal should also be good hygienically and of  good health, free from diseases like Tuberculosis, diarrhoea, sneezing or flue to avoid transfering of bacteria to milk.  Both Milkers and Vendors  should wear clean protective cloth or aprons and their hand should be washed before free from sores, boils, fungus and reduced nails.

> Avoid suddenly sneezing or coughing direct to the milk during milking.

>Filter  the milk immediately after milking inoder to remove foreign particles.

>Never add or remove anything from milk which is not natural to milk such as water, flour, or anything else.

03. Quality of Milk During Storage

> The milk should be stored in a cleaned container that has wide mouth, no clacks,no corners, made of stainless material i.e Aluminium Can which is non corrosive. Be sterilisable by both water and chemicals.

The Quality Aluminium can Vessels for milk storage and transportation.

>Once milk have filtered and  poured into the container, they should be immediately stored in a refrigeration temperature below  3°C to prevent deterioration.

 04. Quality of milk During Processing

> Make sure the heating vessels are cleaned  enough.

 > Avoid underheating to prevent living micro organisms like bacterias, and overheating of milk to prevent caramerisation which leads to browning due to extreme high boiling temperature.

>For yoghurt manufacturing make sure the starter culture is pure and not spoiled or decayed to avoid producing bitter milk product.

05. Quality of milk during packaging process.

Once the milk has been processed they should be packaged in a well improved packaging material inoder to maintain the higher shelf life for proper human consumption. Example of packaging materials are as follows;

Processing and Preservation of Milk Products.

Raw Milk processing into Yoghurt product.

Welcome to my new topic  of Post harvesting technology.

Many peoples fall hardeness on how to manufacture Yoghurt and earn money from their cows raw milk yield. Some times they found themselves that, the harvested milk yield got lossed due to lack of knowledge on how to preserve, and process them into next level and get money cash to boost their living.

Today I'm going to share the principle tips on how to manufacture milk Yoghurt product. 

Materials and tools to prepare;

Raw Milk, Starter Culture ( It can be commercial or natural Starter culture), Heating Vessel, Thermometer for temperature measurement, Cooling Vat/Vessel, Filter funnels, Incubation Chamber/ Vessel, and also refrigerator.

1. Receipt of Milk from the farm production. Make sure raw milk has good quality as produced  from the farm source. It can be tested by using Lactometer test  if it was diluted with water, also milk should be tested before to check if if has undergone spoiled.

2. Filtration of milk

It should be filtered to remove any foreign matters that enterd within the milk during lactating, or transportation from the farm source.

3. Chilling 

The raw milk after milked from the cow, is supposed to be chilled at a refrigeration temperature of (4-6°C) to avoid any deterioration during Yoghurt manufacturing.

4. Heat treatment ( milk pasteurization) at 90°C of the thermometer  within 5 minutes for complete killing  micro organisms.

The high temperature short time heat treatment is applied usually by using  the heat exchanger machines that done in  the industry. But Locally method peoples can heat milk within 25-30 minutes depending to it's volume.

5. Cream Separation 

The cream formed at top layer of heated milk should be removed gently, and leave skim milk alone.

6. Cooling 

The skimmed milk is cooled at the cooling Vat until the thermometer  temperature falls to 42-43°C so as to bring the Yoghurt to the ideal growth temperature for the starter culture.

7. Inocculation of milk with starter culture. The 2-3% of yoghurt starter culture) commercial or natural cultures are mixed into cooled milk.

8.Incubation at 42-43°C for 4-6 hours.

The milk is held at that temperature untill a PH of 4.5 to allow fermentation to progress and form a soft gel and the characteristic flavor of yoghurt.

 

9. Cooling at refrigeration with 5-7°C.

The process is done so as to stop further Fermentation.

10. Addition of Flavor.

 Flavors from Strawbererry, Vannilla, banana can be added before filling and packaging to increase taste to consumers.

11. Filling and sealing at the packaging materials.

The packaged yoghurt.

12. Cold storage of the packaged yoghurt (5-8°C) for consumption.

Processing and Preservation Methods For Perishable Produces. i.e Fruits and Vegetables

 In most Countries the production of many perishable crops is seasonal, this making them to be available only during short period of time within a year. During this short time they are produced in greater quantity than the market capacity, so the surplus of these crops must be processed and preserved to avoid wastage of food and income to the producer.

 The surplus of many seasonal local crops can be preserved for later use by various processing methods requiring only simple, inexpensive equipment.

Processing and Preservation Methods.

>To process and preserve the fresh products successfully, the spoilage agents must be destroyed without ruining the nutritional value or palatability of the produces itself.

  The best methods for small scale processing are; Drying, Chemical Preservation, and heat processing.

      •Drying of produces.

   The aim of drying is to reduce water content of the produce to a level insufficient for enzymes activity or the growth of microorganisms.

  The critical moisture level is about 10-15% moisture content, depending on the commodity( if too much water is removed the product becomes brittle and easily shattered)

 Produces can be dried using solar driying, and Artificial heart.

Solar drying is cheap but is not so easily controlled as drying by more sophisticated artificial methods. It can be done by using direct sun drying or using solar driers 

      The cons of using direct sun drying are as follows;

       > Exposure of produces to dust and atmospheric contamination.

  >Interference from animals and         humans.

    >Insect infestation.

   > No control of Conditions.

Types of solar driers: Direct exposure driers, Indirect exposure driers , A combination of direct and indirect solar drier.

Certain treatments may be given to certain types of produces before drying to maintain the quality of commodity.

     Fruits and Vegetables should  be treated with sulpur dioxide before drying inorder to prevent enzymatic browning, It also slows breakdown of vitamin C and kills some microorganisms 

      Most vegetables except onions and Garlic are blanched by dipping them into hot water for a few minutes before drying; this stops the action of enzymes which may not be killed by sun drying process.

    Green Vegetables retain their color better during drying, if about 0.25% of bicarbonate of soda is added to the blanching water (* but this can speed up the loss of vitamin C)

  Dried vegetables products are subjected to severe insect infestation, and some may be affected by exposure to light during storage; therefore dried products must be stored in a very dry atmosphere in insect proof containers that is away from light.

  • Chemical Preservation

 Chemicals used in preservation includes Sugar, salt , Vinegar, and sodium meta- bisulphate 

       Preservation with sugar 

This is based on using high concentration of sugar with fruit pulp or juices to create a product in which it is difficult for moulds and yeast to grow 

      Jams and Jellies. In these products acidified fruit pulp is boiled with sugar untill the cell  pectin of the fruits form a gel. The hot preserve is sealed in sterilized jars to prevent contamination during storage.

An Example of strawberries Jams.

Apple Jams.

      Fruits Chees. Pulped fruits is sieved and mixed with an equal weight of sugar. The mixture is then heated to remove most of the water. It is then spreaded on trays to cool and dry, then can be cut into cubes and stored under very dry conditions.

     Fruits drink concentrates ( Squashes): Juice is extracted from heated fruit pulp and made into syrup with high sugar concentration. The syrup is then put into sterilized bottles, which are heated in a water bath at 88°C for 20 minutes. The bottles are closed with sterile caps for storage. Drinks are prepared  by dilluting the concentrates with water.

  Preservation with Vinegar  ( pickled vegetables)

      Young Fresh vegetables of many types as well as some fruits can be preserved by pickling in vinegar. The  prepared vegetables or fruits are first soacked for few days in a strong salt solution ( brine )  and then packed into jars, which are then filled cold vinegar. The Vinegar is ussually flavored by steeping desired spices in it for one or two  months. The jars are then covered with plastic lined cover.

    Preservation with Salts 

This method is usually used for preserving green beans, young green beans and salts are placed in alternative layers being of salt the jars are closed with moisture proof covers and then stored on stands. 

   * Fermented Products 

 Vegetables are subjected to lactic acid fermentation in brine  glass of earthenware jars.

    •Preservation using heat treatment.

 For many years fruits and vegetables have been preserved by heat, using canning or bottling methods. The objective is to kill the enzymes and micro-ogarnisms by heating the produce in  liquid in cans or jars. The containers are then sealed while still hot to prevent contamination of the sterilized contents.

   Although moist heat Inactivates  enzymes and kill most micro - organisms some bacteria such as clostridium and staphylococcus are heat resistant and are capable of growing and producing poisons in canned or bottled foods.

Acid foods such as fruits inhibit the growth of clostridium and prevent formation of poison. Non acid foods such as peas, beans  and almost all vegetables can only be preserved by heat at high temperatures achieved  in steam pressure vessels. For this reason, heat processing methods are not recommended for processing any vegetables under small scale local Conditions.

Thanks you so much for following me In my Blog.. The next Topic to be uploaded few days to come, will be Grains Storage and Handling... 

Regards, Brogger Kihombo.

 

How can you reduce post harvesting losses from Perishable crops.i.e Fruits and Vegetables

All Perishable crops are Living plants, containing higher water content to approximately 65-90%, and they are continuing  their living process after harvest. The length of their post Harvest life depends upon to the rate at which they use up their stored food reserves and rate of water loss from the produce. when food and water reserves are Depleted the produce dies and got decayed.

THE FOLLOWING ARE THE MAIN CAUSES OF LOSSES IN HORTICULTURAL CROPS AND HOW TO REDUCE THEM.

01. The losses occured from Physiological Deterioration.

This is due to abdormal physiological changes within the commodity caused by the conditions such as;

> Extremes of Temperature ( high/Low)

>Low atmospheric Humidity

>Physical injury

>Contamination

These  abdormal physiological changes can results into  the following effects to consumers;

>Unpalatable Flavors, Failure to Ripen or abnormal ripening, rotting and decay that makes it to be unfit for human consumptions.

02. Mechanical Damage (Physical Damage) Losses. 

These losses are always happening during harvesting period, transportation of produces, and storaging.

High moisture content and soft texture of fruits, vegetables and root crops makes them highly susceptible to mechanical injury, which can occur at any stage from harvesting to retail marketing.The following are causes that accelerates losses due to mechanical damage;

>Poor harvesting practices

This usually happens when harvestors use abdormal methods like stone throwing, striking with woods or long sticks having nails that normally cause crushing of  fruits and mechanical injuries.

>Use of unsuitable field or marketing containers and crates which may have splintered wood, sharp edges, poor nailing and stapling

>Over packing or under packing of horticurtural produces within  containers during transportation.

>Care less handling such as dropping, throwing, and even walking over the containers having  produces during transportation.

Mechanical  injuries may results into..

>Providing Entry point for micro organisms causing decay i.e Fungi and bacteria.

>Increased water loss from the produces through  damaged zones.

>Causing an increase in respiration rates and heat production.

Now after see the above major causes of Post harvesting losses in Horticultural crops now, we are proceeding next to see on how to reduce the losses.

•ENSURING PROPER PERIODIC   HARVESTING TIME OF THE PRODUCES

Once the fruits or vegetables have reached at maturity stage, they should be harvested soon to avoid over ripening, and even decay while they are in the farm field. The decay can be caused due to micro organisms invation, or wild animals attack. So to avoid such loss, all Perishable crops should be harvested at the specific time without delaying. 

Matured Avocado ready to be harvested.

 

    Unmatured Avocado

•ENSURING PROPER HARVESTING METHODOLOGIES.

The matured horticultural crops should be harvested by using snapping (picking) method and put inside the container, or any improved tools that do not have injury scare like nails, and sharp edges so as to avoid machanical damage losses.

•REDUCTION OF POST HARVESTING LOSSES DURING STORAGE OF FRESH HORTICULTURAL PRODUCES.

 Once the produces are harvested from the field, they should be quickly  reduced their temperature to a recommended storage temperature so as to prevent them from deterioration. This process is known as Pre cooling process. Controlling Storage temperature of produce is very important to  maintain the quality of produces after harvesting. The lower the temperature the lower the deterioration of produces and higher storage time.pre cooling process to the recommended storage temperature is necessary to avoid the following effects..

>Aging due to ripening, softening, texture and color changes

 >Undesirable metabolic changes and respiratory heat production

> Moisture Loss and wilting

>Spoilage due to invation of bacterias, Fungi, and yeast.

>Undesirable growth such as sprouting in root crops and tubers.

>Respiration rates of the commodity

Pree- Cooling process of the Produces..

The following are the methods to be done during pre cooling.. But before pree cooling to be done the following three factors should be considered 

 

>Temperature of produces at the harvest

>The physiology of the produces..the rapid respiring commodities having short post Harvest life should be cooled more rapidly as compared to those with longer Post Harvest Life Produces

> The desired Post Harvest Life of the Produces.

The produces may be Cooled by means of Cold air( room cooling, Forced air Cooling) , Cold water ( hydro cooling), Direct Contact with ice, Evaporation of water from the produce ( Vacuum cooling, Evaporative Cooling).

Once the pre cooling has done correctly, they should be packed well to the improved container that does not have any source of injury like nails, sharp edges of wood. The prefered containers shound be made up of plastic material than of wood material.

Example of matured Avocados that are harvested and stored in the plastic 

Containers ready for transportation to the market.

•REDUCTION OF POST HARVESTING LOSSES DURING TRANSPORTATION OF HORTICULTURAL CROPS.

 

Transportation on  Road way. The losses that inccured during road transportation can be reduced in several ways, mostly important are modification of trucks used to transport fresh produce, handling and stowage practices.

   The trucks used in transportation of fresh produce.

   >Closed vehicles without refrigeration should not being used to carry fresh produce except for very short Journeys.

   >A second whited painted roof can be fixed as a radiation shield 8-10cm above the main roof to reflect suns heat and help to keep produces Cool.

   >The open sided or half boarded trucks can be fitted with a roof on frame. The open sides can be fitted with canvas curtains which can be rolled up or moved aside in sections to allow loading and unloading at any point around the vehicle. Such curtains will protect the fresh produces from the elements but till allow for ventilation

  >Loading and Unloading of Vehicles should be properly supervised to prevent careless handling of packages.

   >Stowage should be carefully done to avoid any collapse of the stow during transport.

  >Packages should not be stacked higher than the maximum capacity as  recommended by the manufacture otherwise the bottom layers may be collapsed  under the weight of above produces.

  >Packed produces should be protected from sunlight and rain at all the times including during loading and unloading.

  

  > Packages should be loaded on dunnage or pallet on the beds of Vehicles In order to allow the circulation of air around the stack during transportation.

   >Avoiding overpacking and underpacking of fresh produces to prevent mechanical Damage.

 

I hope this topic  will help you to reduce the losses to your Horticultural produces... 

The next section will be Processing and 

PRESERVATION OF FRESH HORTICULTURAL PRODUCES..