|Year-round Monitoring of Aflatoxins in Milk Samples from Dairy Farms Countrywide and Examining the Correlation between Its Concentration in Milk and in the Livestock Feed
This research program was financed by the Dairy Board Research Fund
Research Study No. 339/0013/10
Shmulik Friedman –Israel Dairy Board; Ran Solomon – Cattle Department, Professional Training Center (Shaham); Miriam Freund – Plant Protection Services; Malka Britzi and Stefan Sobak – Veterinary Services' Laboratory for Testing Residues in Products of Animal Origin; Shuki Miron, Vulkani Institute and Allen Schlusberg - Veterinary Services
Purpose of the Study
1. Year-round monitoring of aflatoxin concentrations in raw milk samples in dairy farms countrywide and examining the correlation between its concentration in milk and in the feed of farm animals.
2. Perform a controlled challenge test by administering B1 in feed to Israeli cows and try to determine their ability to secrete the M1 metabolite in milk (CO – carry over).
3. Based on the results, try to identify the risk factors of secreting B1 of the various feed stuffs comprising the ration of dairy cows in Israel, and try to determine a means of control as well as recommendations to nutritionists in determining the optimum permissible ration.
1. The study did not prove a direct and immediate correlation between the presence of B1 in feedstuff and the detection of M1 in milk from the same farm.
2. It was found that there is a possibility for the fungus to develop and to secrete toxin also in the locally produced feed (not just the imported and shipped by sea).
3. Conditions for the production of the toxin in various feedstuffs could exist all year round. According to this study, the most prevalent months for the appearance of the toxin in food is from the beginning of spring to fall.
4. It was found that feed with the highest risk of toxin presence is corn silage and other corn kernel by-products. It should be noted and emphasized that all the results obtained in this study to check the presence of the toxin in corn products as in other feedstuffs did not deviate from the permissible standard.
5. The Israeli cow has a higher carry over rate of B1 to M1. The reasons for this apparently have to do with its increased milk production output based on genetics, overall nutrition and increased milking frequency (three times a day). This subject calls for further research to obtain more explanations than those offered in this study.
6. It was not proven that the toxin has an effect on a higher somatic cell count or on inter-udder infections or other diseases, and there is a need for more comprehensive studies on this subject.
7. When putting together the dairy cow feed ration, nutritionists and feed center managers must also consider the possible quantitative result of the presence of B1 in the total ration. Any deviation from the standard in the total ration requires searching for the source of the contamination in the ration ingredients and removing them immediately or quantitatively reducing their use in order to meet the required standard for dairy cows.
8. Based on all the results obtained over the past three years, it can be concluded that notwithstanding the risk of the formation of the B1 toxin in various feedstuffs (both imported and local) and notwithstanding that it has been proven that the Israeli cow has a high carry over (CO) rate, this study did not find values that exceed the required standards. The appearance of irregularities in the past indicates that changes in growing and irrigation methods, weather, collection, transport and storage of feedstuff all might – under certain conditions – cause a rise in values exceeding the permissible toxin levels in feedstuff and milk.
9. The results of this study demonstrate that the feed safety standard provided to livestock in Israel is good and covers both imported and homegrown feedstuff. At the same time, it is recommended that the relevant authorities adopt a procedure that requires regular monitoring of all sources of feed and locating the risk factors before they enter milk and dairy products. This is in the aim of continuing to safeguard public health and to comply with the European standards and requirements for milk and dairy product safety.