To an economist a can of beans is a noncyclical good. When jobs grow scarce, consumers are quick to decide against new car purchases and flights to Bermuda but are unlikely to change their chili recipes. For that reason, shares of food makers have long been regarded as defensive investments. Returns are modest in a rising market -- but so are losses in a falling one.

True to form, packaged food companies within the S&P 500 index lost just 7% of their value this year through mid-October, while the overall index plunged 36%. Some food stocks are soaring. Cereal maker General Mills (GIS) has gained 19% since this column recommended the stock in February, outperforming the market by 50 percentage points.

Therein lies a dilemma. Pantry items provide steady sales but not fast growth. Companies that make such products, then, ought to sell for cheap. But while the S&P 500 has been pummeled to 12 times this year's earnings forecast, big packaged food companies fetch more than 14 times earnings. Dividend yields, which I've lately argued are more telling than price/earnings ratios in a down market, tell a similar story. The S&P 500 carries an alluring 3.6% yield. Big Food pays just 2.9%. So which is more defensive: a noncyclical business or one with a modest valuation? If beans indeed sell better than cars and flights for a while, will they do so by enough to make General Mills' P/E of 17 a better deal than the 5 and 6 P/Es worn by seatbelt maker Autoliv (ALV) and airplane interior specialist BE Aerospace (BEAV) ?

Fortunately, some food aisle names still look cheap. Two weeks ago I highlighted J.M. Smucker (SJM) . More recently, Sara Lee (SLE) turned up in a search for low price/sales ratios and plump dividend yields. The Downers Grove, Ill., company makes bread, deli meats, sauces and sweets under its namesake brand. It also owns Ball Park franks, Jimmy Dean and Hillshire Farm sausages, a handful of gourmet coffee lines, some nonfood businesses like Kiwi shoe polish and more.

While Smucker has a long history of outperforming the broad stock market, Sara Lee surely does not. It has held up a touch better than the average stock this year, but 10-year shareholders are down more than 60%, not counting dividends. Moreover, Sara Lee isn't especially profitable. It turns just eight cents of each sales dollar into operating profit. That's a nickel less than Kraft (KFT) . But over long time periods, margins tend to revert to industry averages as struggling companies fix their mistakes and top-performing ones find it difficult to improve on excellence. Subpar margins can be a welcome sign if they come with reason to believe improvements are afoot.

Sara Lee is in the third year of purging unprofitable businesses. Sales are expected to total just under $14 billion during the company's current fiscal year, which runs through June. That's $2 billion less than the company rang up four years ago. Divestitures from the past year include a line of lunch meats in Mexico as well as food-service sauces and dressings in the U.S. Sara Lee's adjusted operating margin, while relatively modest, improved by three-quarters of a percentage point over the past year while those of peers fell amid rising grain, milk and meat costs. Ingredient costs are now falling in concert with crude oil. Sara Lee stands to benefit doubly -- from the improving margins analysts expect for all food makers and from the continuing ones born of its efficiency drive.

Perhaps it's early to bet on Sara Lee's turnaround. A long-term dog needs more than a few quarters of messy improvement to win investors' trust. But shares carry low expectations at just 11 times this year's earnings forecast, and stockholders get a 3.6% dividend yield. That makes Sara Lee one of the rare defensive food stocks that still trades at a defensive price.

Have a look if you like at all six companies that survived my recent price/sales screen. Run your own search anytime using SmartMoney's stock screener and the full list of search criteria (below).

Price/sales Screen Recipe

• Price/sales ratio below 1.0
• Price/sales ratio below industry median
• Trailing 12-month free cash flow positive
• Dividend yield greater than 3%
• Trailing 12-month sales greater than $500 million
• Past quarter sales growth positive