FOCUS ON INGREDIENT QUALITY-
MYCOTOXIN AND BACTERIAL SURVEILLANCE

Ben Jones, Assistant Director, The Office of the Texas State Chemist
and Ryan Izard, Director of Technical Services

Livestock and pet food manufacturers continually guard against contamination from mycotoxins. More recently, interest in other contaminants such as bacteria has grown. One regulatory agency that has been monitoring these contaminants in ingredient supplies is The Office of the Texas State Chemist (OTSC). This update provides data from OTSC mycotoxin and bacterial surveillance programs and should help the feed industry focus on manufacturing safer products for livestock and pets.

Aflatoxin in corn and milo

Interest in mold toxin levels in grain is heightened when the new crop harvest rolls in. Because the U.S. grain harvest begins first in south Texas and moves northward with the maturing crop, OTSC is in a unique position to give early notice of crop contamination. OTSC investigators survey grain as it moves from field to elevator. This year’s harvest has moved north and results from the mycotoxin surveillance sampling program are nearly complete. The harvest of new crop corn and milo is finished in South Texas, the coastal bend, the blacklands of Central Texas, Northeast Texas and the Red River Valley. At this time, only the harvest in the south plains around Lubbock and the Oklahoma and Texas panhandles remain.

The prevalence of aflatoxin in corn is high this year. FDA and state laws restrict grain’s use when it contains more than 20 ppb aflatoxin. Sixty percent of the 359 samples collected so far this season contain aflatoxin greater than 20 ppb. The results of the survey are graphed in the figure. The 60% can be divided into categories based on the amount of mycotoxin: 17% of the samples were between 20 and 50 ppb, 13% between 50 and 100 ppb, 15% from 100 to 200 ppb, 6% ranged 200-300 ppb, 4% fell between 300 and 500 ppb, and 5% were over 500 ppb. On the extreme upper end of contamination, 4 samples collected were over 1000 ppb. Aflatoxin was not found in any of the milo samples collected.

FDA guidelines and state commercial feed rules limit the ways that contaminated grain may be used. For grain containing aflatoxin, the following rules apply:

Fumonisin in corn

Although aflatoxin contamination in corn is elevated this year, the prevalence of fumonisin is low. Among surveillance samples, only 3% contain fumonisin at greater than 5 ppm. This includes 2.5% between 5 and 10 ppm and 0.5% over10 ppm.

The guidelines for using grain containing various levels of fumonisin are:

A great tool on the OTSC website (www.otscweb.tamu.edu) to keep informed of the latest results of the Texas harvest is the continuously updated maps for aflatoxin and fumonisin in corn and aflatoxin in milo. Fly over “Education” and click on “Best Management Practices”, (or browse directly to www.mycotoxinbmps.tamu.edu/welcome.aspx) and select “Maps”. The map provides the most up-to-date information by county showing the highest levels of mycotoxins reported. 

Microbiological survey results

Regulatory agencies are increasingly interested in the bacterial presence in feed ingredients. Two potential food-borne pathogens receiving focus are Salmonella species and E. Coli O157:H7. OTSC performed microbiological surveys of ingredients in FY 2007 – 2009 to establish baseline information on these bacteria. Samples included rendered animal protein products, animal protein product blends, oilseed meals, and animal feeds. The results were compiled using basic simple statistics to explain features of Salmonella and E. Coli O157:H7 positive feed samples with respect to inspection area, product class and season.

So far in the study, 1531 feed samples have been collected. One hundred and twenty two (7.97%) were Salmonella positive and were manufactured by 70 out of 468 feed firms. Most of Salmonella positive samples in the present data set were categorized under two product classes, animal protein products (47 out of 122) and beef cattle feeds (20 out of 122). Notably, Salmonella positive samples from animal protein products were a major portion (38.5%) of total Salmonella positive samples.

Interestingly, the overall Salmonella incidence during each of the three years studied has steadily increased. In FY 2007 3.58% were positive, increasing to 8.81% in FY 2008 and further to 11.46% in FY 2009. Within the category containing the highest incidence of salmonella contamination, animal protein products, the percent positives were 25.5% in FY 2007, increasing to 43.1% in FY 2008, and falling back to 26.1% in FY 2009. Percents of Salmonella positive samples were markedly different among individual months in which the analysis was completed. However, the differences were not seasonally consistent.

There were no samples collected in FY 2007 – 2009 positive for E. Coli O157:H7.

Focus on feed hygiene

FDA has highlighted Salmonella as an important hazard that threatens feed hygiene and animal and human health. In 21 CFR 500.35, FDA specifically named Salmonella as an adulterant in animal feeds and ingredients. OTSC has strongly promoted HACCP education over the past several years, and controlling Salmonella has become an integral part of many HACCP programs. FDA has also included Salmonella contamination limits in the draft framework of their “modernized” Animal Feed Safety System (AFSS). Current feed laws prohibit poisonous or deleterious substances that may render the feed injurious to animals under ordinary conditions of use. Effective HACCP programs help feed suppliers intervene in the chain of events that might put animal or human health at risk. Bacterial contaminants and mycotoxins pose such risks.

Regulatory surveillance programs help define vulnerable areas and allow industry to focus efforts to specifically control those risks. Increasing industry’s focus on feed hygiene translates into more protection against mycotoxins and bacterial adulteration, meaning more responsible and safer food products for livestock and pets.