The maximum fall was witnessed in dairy prices.
The FAO's price index, which measures monthly price changes for a basket of grains, oilseeds, dairy, meat and sugar, averaged 207.8 points last month as compared with 214.6 points in May 2013, falling nearly 3.2 per cent.
Global Food Price Index showed a sharp jump in June.
Global food prices rebounded in January this year demonstrating the volatility in the international food markets, after falling for six months since July, 2011, United Nation's body FAO said on Friday.
The current situation offers an opportunity for farmers to reinvest in agriculture.
According to the Food and Agriculture Organisation, global food prices fell for the first time after eighth consecutive months of price spikes in March this year in the wake of a decline in international prices of oil, sugar and cereals.
The FAO price index measures monthly price changes for a basket of cereals, oilseeds, dairy products, meat and sugar.
Dairy, sugar prices fall sharply, despite El Nio fears
It would also be the fifth month of consecutive drops in the index.
FAO's Food Price Index is a monthly measure of change in international prices of 55 commodities.
The fall in global prices resulted in a drastic decline in the Food Price Index compiled by the United Nations' Food and Agricultural Organization. Based on the prices of a basket of internationally traded food commodities, the FAO Food Price Index averaged at 203.9 points in July, down 4.4 per cent (2.1 percentage point) from a revised value in June. This level was seen earlier in January, at 203.2 points.
Higher local output estimated to depress cross-border sales
Trend could continue on downward revision in winter harvests.
The FAO's food index of 55 items averaged at 209.3 points in April this year, down by 1.6 per cent from March and 3.5 per cent below April 2013.