When the going gets tough, the tough go … shoplifting. That’s the consensus of nearly 8,000 grocery retailers who responded to the Food Marketing Institute’s “2009 Supermarket Security and Loss Prevention” survey.

“Historically, an economy in trouble often leads to an increase in theft-related loss” for grocers, concluded researchers at FMI, an Arlington, Va.-based trade association for food retailers and wholesalers. But the good news is that after three years of increases, retailers reported that theft-related losses were down in 2008, which “demonstrates that loss prevention is back on track as the economy rebounds,” FMI researchers say.

Nevertheless, loss due to shoplifting, employee theft, vendor theft, burglary and other fraud accounted for a median of 1.9 percent of supermarkets’ total retail sales in 2008, according to the FMI report.

The bottom line: Whether you have one store or 100, theft can subtract thousands of dollars from your annual profits. In fact, the smaller your store, the more vulnerable you may be because you have fewer resources to put toward security systems. But there are a variety of inexpensive yet effective ways to reduce thefts. Here’s what security experts recommend to combat the four biggest types of store loss: shoplifting, employee theft, vendor fraud and burglary.