Check out the latest Coca-Cola, PepsiCo, and Enbridge earnings call transcripts.

Most income investors adore the Dividend Aristocrats of the S&P 500, which have earned the elite title by hiking their payouts annually for 25 years or more. However, some Dividend Aristocrats are better long-term investments than others -- since they might have more sustainable business models, wider moats, and healthier cash flows. Let's take a look at three Dividend Aristocrats investors can consider holding forever: Coca-Cola (NYSE:KO), PepsiCo (NASDAQ:PEP), and Enbridge (NYSE:ENB).

Leo Sun (Coca-Cola): Coca-Cola might not be considered a great "forever" investment, since health-conscious consumers are shunning its flagship sodas across the world. Soda consumption in the US, for example, recently fell to its lowest point in over 30 years. However, Coca-Cola expanded its beverage portfolio well beyond its flagship sodas to counter that shift.

The company now sells a wide range of juices, teas, energy drinks, bottled water, and other noncarbonated beverages. It owns a major stake in energy drink maker Monster Beverage (NASDAQ:MNST), and it recently acquired UK coffee chain Costa Coffee. It has also launched low-calorie and zero-calorie versions of its sodas, and repackaged them in smaller cans and bottles.

That's why Coca-Cola still expects its organic sales to rise at least 4% this year and its adjusted earnings to grow up to 10%. It currently pays a forward dividend yield of 3.3%, and it's hiked that payout annually for 55 straight years.

Coca-Cola's earnings and free cash flow-based payout ratios both exceeded 100% over the past 12 months, but those figures were distorted by the refranchising of its bottling operations, asset impairment charges, restructuring costs, investments, and other one-time charges. Excluding those charges brings its payout ratios back below 100% -- which indicates that Coca-Cola won't lose its Aristocrat title anytime soon.

Drink up with this stock

Dan Caplinger (PepsiCo): Consumer goods stocks are a great place to look for dividend winners, and as Leo notes with his pick of Coca-Cola, beverage companies in particular have fared quite well. But I'm coming out on the other side of the Pepsi Challenge with my pick, because despite having a slightly smaller drinks business, PepsiCo has the power of diversification on its side.

PepsiCo makes a lot more than just its namesake cola. The company's Frito-Lay division is a giant in the food industry, producing potato chips, pretzels, and countless other snacks. Under previous CEO Indra Nooyi, PepsiCo embraced the trend toward healthier food early on, allowing it to get a competitive advantage over Coca-Cola on the beverage side of the business while pivoting its snack offerings to cater to health-conscious consumers. Now new CEO Ramon Laguarta will have a chance to put his distinctive mark on PepsiCo's business, and it'll be interesting to see what if any differences in strategic vision emerge.

For dividend investors, though, PepsiCo has plenty of credibility. For 46 straight years, the beverage and snack company has delivered increased dividends, including its most recent 15% payout boost back in June. The stock's yield of 3.4% just edges out Coca-Cola, and shares have held up quite well in the recent market downturn. For those seeking a long-term play on much-loved consumer products, PepsiCo makes a great stock investors can comfortably hold for the long run.

Almost there with plenty of fuel to continue growing

Matt DiLallo (Enbridge): Canadian energy infrastructure giant Enbridge isn't yet a Dividend Aristocrat since it has increased its payout for only 24 consecutive years. However, the company recently reaffirmed its near-term outlook, including plans for another dividend increase next year. Further, the pipeline company provided an initial glimpse at its longer-term view, which suggests it should have plenty of fuel to continue increasing its dividend.

Enbridge's latest dividend increase was 10%, which is its targeted raise for next year as well. The company can fully support that payout since it's on pace to grow its cash flow per share at that same rate. Further, with 98% of its cash flow supported by stable sources like long-term contracts, and a conservative payout ratio of less than 65% to go along with a strong investment-grade balance sheet, Enbridge's dividend is on rock-solid ground.

Meanwhile, Enbridge stated that it expects to grow its cash flow at a 5% to 7% annual rate post-2020 while maintaining an ultraconservative financial profile. Driving that growth are the expansion projects the company recently secured as well as those it has in development. Enbridge should have no shortage of opportunities beyond those it has already identified, given that the North American energy industry needs to invest more than $800 billion in building new oil and gas midstream infrastructure through 2035. These future expansions should give Enbridge the funds to continue increasing its dividend for years to come.

With a long history of sending more money to investors, a sound financial profile, and ample fuel to keep growing, Enbridge is an ideal dividend stock to buy and hold for the long haul.