Updated from April 21, 2015 to include details on the availability of pork menu items, plans to increase prices, and a new delivery service.

NEW YORK (TheStreet) -- Investors dumped shares of burrito giant Chipotle (CMG) - Get Chipotle Mexican Grill, Inc. Report in after-hours trading on Tuesday and into trading on Wednesday as notoriously heady sales growth cooled and execs warned of a further slowdown this spring. 

But, the overall picture for the "healthy" fast food chain may be better than many realize. 

Chipotle, which just finished up its first "Cultivate" food and music festival of the year, reported earnings of $3.88 a share versus the consensus estimate of $3.66 a share. But same-restaurant sales rose 10.4%, slower than the huge 16.1% gain achieved in the fourth quarter. Chipotle execs pinned the slower sales growth, which continues to soundly outpace the likes of struggling McDonald's MCD and hot upstart "better burger" purveyor Shake Shack (SHAK) - Get Shake Shack, Inc. Class A Report, on inclement weather in the Northeast and not having pork carnitas in one-third of its restaurants. In January, Chipotle suspended a relationship with a key pork supplier that was not operating up to its standards, causing it to remove a popular menu item in many of its locations. 

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The more mild pace of sales growth in the quarter, as well as comments that sales in April will likely moderate further to a high-single digit percentage gain, rattled investors who have bid up the stock some 38% in the past year. Chipotle's shares slumped nearly 5% in after-hours trading and were down over 7% in morning trading on Wednesday.

As the menu item returns, Chipotle stands to receive another jolt to the top line from another round of price increases. The company, which has historically been reluctant to lift prices, confirmed it will hike prices on steak and barbacoa in the third quarter by 4% to 6% in order to compensate for persistent beef inflation.

In the second quarter last year, Chipotle implemented an across-the-board menu price increase of about 7%, as it dealt with beef, dairy and avocado inflation. Same-restaurant sales growth accelerated soon after the menu price increases went into effect -- after rising by 13.1% in the first quarter of last year, same-restaurant sales increased averaged 17.7% in the remaining three quarters.

Chipotle's first quarter earnings beat was also supported by a 60-basis-point decline in food costs year over year as the price of several ingredients fell, something that may stay intact in coming quarters. Specifically, most of the decline was attributed to falling dairy costs, along with a drop in the price of avocados.

"We were snakebitten in other quarters, but in this quarter everything was calm," said an executive on the earnings call on the topic of dairy and produce inflation.  And, as TheStreetreported on Mar. 19, Chipotle will be rolling out a delivery service with courier network Postmates, which should support sales. According to Chipotle, its relationship with Postmates will cover 64 cities in 24 major metro markets, which was characterized by execs as a "nationwide" rollout of the delivery platform.    

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.