Walk down the baby-food aisle of any grocery store, and parents will be hard-pressed to find jars of pureed citrus fruits without a key ingredient -- ascorbic acid -- from China.

Shoppers are also likely to find that a portion of some juice concentrate in any finished juice box is from China.

Over in frozen foods, at least one ingredient from China is likely among the dozens packed in many frozen pizzas.

Then there are all the finished products from China -- from canned mushrooms to frozen vegetables, from nuts to fish fillets.

As China wrestles with a growing food-safety scandal linked to contaminated milk products, consumers in Canada are faced with a simple fact: in the last decade, China has climbed its way up the importer list, to third spot last year behind the United States and Mexico from 11th spot in 1997.

The quantity of imports of finished goods and ingredients from China has spiraled to 560 million kilograms, worth about $818 million, from about 91 million kilograms totalling about $213 million.

"If it doesn't say, Made in China, you have no idea what Chinese ingredients are in there. You'll never know," said James Morehouse, senior partner at Chicago-based A.T. Kearney and specialist in the Chinese food industry. "If you go through a supermarket, there's probably China-sourced or India-sourced ingredients in the vast majority of the products."

As companies seek out cheaper ingredients and food products, they often land in China -- even though some are reticent to disclose details.

Coca Cola Company Ltd. offers more than 450 brands comprising more than 2,800 beverage products, including juice and energy drinks. Amy Laski, spokeswoman for Coca Cola Canada, confirmed the corporate giant does "source several ingredients from China, but our policy is not to disclose where we source specific ingredients.

"In terms of quality and safety of our ingredients that do come from China, those are second to none."

The key question for consumers, says Morehouse, is whether there are there enough checks -- in China and at the Canadian border -- to ensure Chinese food imports are safe.

He can't be absolutely certain in all cases.

Morehouse, an expert in food safety and the supply chain, has made about a dozen trips to China in the last four years, returning from his most recent trip earlier this week.

China has a two-tier food inspection system that provides checks for finished products destined for the international market. Food products for the Chinese domestic market are the foundation of a largely unregulated industry that operates under a "completely different set of rules," said Morehouse.

The scandal involving milk products contaminated with melamine are part of this domestic system; so far, four infants have died and tens of thousands have become sick after digesting infant formula laced with melamine.

"If it's made in China and it's inspected by the Chinese government before it's exported -- and all of it's supposed to be -- and if there is an aggressive inspection program as it enters in Canada, then chances are it's OK," said Morehouse.

But there are gaps in the way China inspects food products destined for store shelves in Canada and elsewhere around the world. There is also a less rigorous approach to ingredients exported from China destined for food products manufactured in Canada and elsewhere, Morehouse said.

Chinese authorities do not run comprehensive tests on finished products leaving China, he said. And the tests they do run don't necessarily include the same Canadian consumers would expect them to run.

"You've got fish who swim in polluted water. They're polluted. Did they check for all the pollutants? Probably not."

Generally, China focuses on the conditions of the manufacturing plants producing the food, Morehouse added.

"It probably means they inspected the plant and found the plant is adequate. But I've complained to Chinese authorities for a long time. They generally do not inspect raw material coming into the plant. They inspect something going out of the plant, but you don't know whether something is buried in there."

But "at least there's a check" for finished products. The same cannot be said for ingredients in all cases, said Morehouse.

Companies that turn to China for ingredients say they do their own due diligence to make sure they're safe.

Along with the vast majority of manufacturers of baby food, H.J. Heinz Company of Canada gets its ascorbic acid for some of its fruit puree from China.

Spokeswoman Joan Patterson said the company looked for other options, but found China was the only place it could source the vitamin.

"We've been the No. 1 baby food for over 70 years in Canada, so people really trust us. We work with the same suppliers, so we carefully screen all of our suppliers.

"We also test ingredients before we put them in products and we're testing for product safety all the way through the system because we want people to make sure they can always trust the Heinz product."

Like all manufacturers of infant formula for sale in Canada, Nestle Canada does not get any of its milk products from China. The company does, however, "source a small amount of micronutrients from China as a minimal part of the product" for its infant formula and some cereals because they're not available elsewhere, said spokeswoman Catherine O'Brien.

AGENCY'S ROLE

The Canadian Food Inspection Agency is charged with making sure the food for sale in Canada is safe. Part of that job includes working with the Canada Border Services Agency to keep tainted or illegal food imports out of the country.

What CFIA has done in recent days as a result of the growing contaminated milk scandal in China:

Recalled on Thursday Chinese-made White Rabbit cream candies after products in New Zealand and Singapore were found to contain high levels of melamine. WhiteRabbit candies have been found at stores in Chinatowns in Canadian cities.

Recalled on Monday Mr. Brown 3-in-1 instant coffee products, distributed in B.C., Alberta and Manitoba, after being informed they may contain melamine.

Last week, recalled Chinese-made Nissin Cha Cha Dessert after officials in Hong Kong found some of the products for sale there contained melamine.

Issued border lookouts for all milk products from China and any processed foods containing milk ingredients from China. To date, CFIA has tested more than 65 products and "all are clear," said Garfield Balsom, a food-and-safety recall official with CFIA. "At this point in time, there has been no positive findings from our surveillance."