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How to control microbial load and aflatoxin in organic food sector?

Started by , Sep 17 2008 02:14 PM
10 Replies
How to control microbial load and aflatoxin in organic food sector?
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Dear Adiga,

You can refer the guidelines on “Guide to Minimize Microbial Food Safety Hazards
for Fresh Fruits and Vegetables” from Center of Food Safety and Applied Nutrition and US FDA.

http://www.cfsan.fda...s/prodguid.html
Did you manage to take a look at the link Jean provided Adiga? If you have further questions please let us know.

Regards,
Simon
Sarara, could you please help me out?
I read an article from Mexico that stated that mycotoxins in corn could be eliminated to a certain degree by nixtamalization (boiling corn with lye). What would be the chemical reactions behind this reasoning? From what I´ve read in other places, the best you can do (usually in animal feed) is to use sequestrants.
Also, is there some link between mycotoxins and cleft lip? There seems to be a high incidence of cleft lip in my country. Most farmers grow their own corn and agricultural methods are not very advanced.
Dear MRios,

I found the following on wikipedia:

Nixtamalization typically refers to a process for the preparation of maize (corn) in which the grain is soaked and cooked in an alkaline solution, usually limewater, and hulled. The term can also refer to the removal via an alkali process of the pericarp from other grains such as sorghum. Maize subjected to the nixtamalization process has several benefits over unprocessed grain for food preparation: it is more easily ground; its nutritional value is increased; flavor and aroma are improved; and mycotoxins are reduced. These benefits make nixtamalization a crucial preliminary step for further processing of maize into food products, and the process is employed, using both traditional and industrial methods, in the production of tortillas, tamales, corn chips, hominy and many other items.

The Nixtamalization process


The first step in nixtamalization, kernels of dried maize are cooked in an alkaline solution at or near its boiling point. After cooking, the maize is steeped in the cooking liquid for a period. The length of time for which the maize is boiled and soaked varies according to local traditions and the type of food being prepared, with cooking times ranging from a few minutes to an hour, and soaking times from a few minutes to about a day.

During cooking and soaking, a number of chemical changes take place in the grains of maize. Because plant cell wall components, including hemicellulose and pectin, are highly soluble in alkaline solutions, the kernels soften and their pericarps (hulls) loosen. The grain hydrates and absorbs calcium or potassium (depending on the alkali used) from the cooking solution. Starches swell and gelatinize, and some starches disperse into the liquid. Certain chemicals from the germ are released that allow the cooked grains to be ground more easily, yet make dough made from the grains less likely to tear and break down. Cooking changes the grain's protein matrix, which makes proteins and nutrients from the endosperm of the kernel more available to the human body.

After cooking, the alkaline liquid (known as nejayote), containing dissolved hull, starch, and other corn matter, is decanted and discarded (or sometimes used in producing amatl). The kernels are washed thoroughly of remaining nejayote, which has an unpleasant flavor. The pericarp is then removed, leaving only the germ of the grain. This hulling is performed by hand, in traditional or very small-scale preparation, or mechanically, in larger scale or industrial production.

The prepared grain is called nixtamal. Nixtamal has many uses, contemporary and historic. Whole nixtamal may be used fresh or dried for later use. Whole nixtamal is used in the preparation of pozole and menudo, and other foods. Ground fresh nixtamal is made into dough and used to make tortillas, tamales, and arepas. Dried and ground, it is called masa harina or instant masa flour, and is reconstituted and used like masa.

The term hominy may refer to whole, coarsely ground, or finely ground nixtamal, or to a cooked porridge (also called samp) prepared from any of these.




Enzymatic Nixtamalization
An alternative process for use in industrial settings has been developed known as enzymatic nixtamalization which uses protease enzymes to accelerate the changes that occur in traditional nixtamalization. In this process, corn or corn meal is first partially hydrated in hot water, so that enzymes can penetrate the grain, then soaked briefly (for approximately 30 minutes) at 50°-60°C in an alkaline solution containing protease enzymes. A secondary enzymatic digestion may follow to further dissolve the pericarp. The resulting nixtamal is ground with little or no washing or hulling.

By pre-soaking the maize, minimizing the alkali used to adjust the pH of the alkaline solution, reducing the cooking temperature, accelerating processing, and reusing excess processing liquids, enzymatic nixtamalization can reduce the use of energy and water, lower nejayote waste production, decrease maize lost in processing, and shorten the production time (to approximately four hours) compared to traditional nixtamalization.[5]

Effects of enzymatic nixtamalization on flavor, aroma, nutritional value, and cost, compared to traditional methods, are not well-documented (http://en.wikipedia....Nixtamalization, 2009).





I would like to search more now but I dont have time. I will try later!

Cheers!

Filip

I also found this:

"A fungal metabolite, secalonic acid, induced cleft-lip palate and open eyes in mouse fetuses following intraperitonial injection and eye, brain, limb, digits and tail defects in fetuses of rat dams injected subcutaneously on various days in gestation" in the following text:

Teratogenic activity of mycotoxins

and this:

"Although orofacial clefts (cleft lip or palate or both) are not considered a developmental disability per se, there is evidence of an assossiation between their occurence and maternal nutrition as well as a rationale for the potential contribution of several nutrients..." (more on the following link).

Spina Bifida and other birth defects

Cheers!
Filip

Sarara, could you please help me out?
I read an article from Mexico that stated that mycotoxins in corn could be eliminated to a certain degree by nixtamalization (boiling corn with lye). What would be the chemical reactions behind this reasoning?


If there is anybody still interested in this question, on the book that SaRaRa kindly linked, on page 69 almost last sentence in relation to the 54th reference, you can find a possible reason fro the degration of aflatoxins in maiz.

http://books.google....N...;q=&f=false

Other references mention that most of the initial concentration of aflatoxins is lost during steeping.

Food_safety_information_papers_corn_milling_association_mycotoxins.pdf   140.3KB   63 downloads

Regards,

FSSM
Thank you FSSM. I tried to look for page 69, but it said that it wasn´t part of the book preview.
Thank you also for the second article. It refers mostly to wet corn milling, and our company basically makes masa flour in one installation and corn grits where I work. From our data, aflatoxins are rarely found in the corn grits, sometimes found in corn bran which is sold for animal feed.
Any other information on the topic would be greatly appreciated.
Hi !

Sorry you can´t see the page, I will copy for you when ever possible.

What are the steps in your process (nixtamlalization)?

It seems that there are two ways of reducing the risk of aflatoxins:

a) Good Agricultural Practices: taking care that your corn won´t be infected at field and during warehousing.
b) At your facilities: excluding contaminated raw material, during process.

Would your company be able to control the GAP with your suppliers of corn?
There seems to be some Biopesticides that could help control aflatoxins.

Your process might already be diminishing the starting concentration of aflatoxins if you use wet milling.

Regards,

FSSM
I hope this helps...

The book you couldn´t see:

The thermal and alkaline treatment to which the corn is subjected during nixtamalization hydrolyzes the lactone ring of the aflatoxin molecule, generating a salt that might be solubilized and further decarboxylated54.




http://pubs.acs.org/....1021/jf0007030

Other possible useful information:

http://www.sciencedi...a6be5e037613ef7


Page 206 (Chapter 9.7)
http://books.google....h...ran&f=false


http://www3.intersci...l...=1&SRETRY=0

These articles:


Biological_control_of_aflatoxin_contamination_of_crops.pdf   525.66KB   48 downloads


Reduction_of_Mycotoxin_by_Bacillus_spp._Isolated_from_Fermented_Soybean.pdf   95.09KB   37 downloads

Regards,

FSSM

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