Standing in front of the chicken section of the grocery store is an onslaught of ambiguous yet vaguely appealing labels. Despite presumably being made of the same ingredient (chicken), products vary dramatically in price and appearance and are covered with a potpourri of pseudo-helpful labels like "all-natural", "hormone free", and my personal favorite, "air chilled". While some labels provide customers with obvious and helpfully decodable information about the product (ex: "breast" and "skin on"), describing anything as "air chilled" is particularly baffling to me. Many questions come to mind...I'm hanging out in some air right now myself, does that make me air chilled too? Is this the same as putting chicken in the fridge? Is this a label that indicates regulation or is it simply marketing? Will this make my chicken more expensive, and is the benefit worth the extra money?
Chicken in the USA
Let's start this demystification with a brief discussion of the US poultry landscape. According to the USDA, chicken is the number one species consumed in America. Production is big business as well: the US poultry industry processed 8.6 billion chickens in the year 2012 compare that to just 32.1 million cattle (North American Meat Institute). The USDA classifies meat chickens (vs layers, or chickens used primarily for egg production) into 6 categories, the most important of which is the Broiler-Fryer, or young chickens killed at around 7 weeks old and weighing in at between 2.5-4.5 lbs. Other categories include such oddities as the Capon (a surgically unsexed male chicken between 16 weeks-8 months in age) and the Rock Cornish Game Hen, weighing in at only 1-2 lbs. As mentioned, Broiler-Fryers make up the vast majority of commercial chicken production, so you can rest assured that the chicken parm you had for dinner last night was probably not "surgically unsexed".
Back to the Topic of Chicken Chilling
I suppose that this fact will be obvious once you think about it: chickens are warm when they are slaughtered, as the average body temperature for a healthy live chicken is around 106 degrees Fahrenheit. Post kill, warm chicken carcasses are a hotbed for the growth of bacterial pathogens (fun stuff like Campylobacter, Listeria and Salmonella) that can cause foodborne illness in consumers. These bacteria are picked up by live chickens through the ingestion of infected feces or insects and settle in the intestines, so they can easily wind up on the carcass post slaughter (and subsequently infect unlucky consumers) . The USDA's Food Safety and Inspection Service (FSIS) would very much like to avoid these bacteria spreading to the public, so producers are required to bring the temperature of their carcasses down to below 40 degrees Fahrenheit within 4-8 hours of slaughter. This process is known as chilling and is somewhat effective at inhibiting the growth of bacteria on poultry.
Air Chilling vs Immersion Chilling
Now we know that chickens are chilled in order to be safe for consumption and that all of the chicken seen in the grocery store were in fact chilled after slaughter. So what is air chilling, what are the alternatives, and which method is best for food safety and for flavor?
There are 2 major methods to accomplish the chilling of raw poultry: immersion chilling and air chilling. Air chilling is an emerging alternative to immersion chilling in the US and is defined by the FSIS in the following way: "air chilling is the method of chilling raw poultry carcasses and parts predominantly with air. An anti-microbial intervention may be applied with water at the beginning of the chilling process if its use does not result in any net pickup of water or moisture during the chilling process. The initial anti-microbial intervention may result in some temperature reduction of the product only if the majority of temperature removal is accomplished exclusively by chilled air.”. In English, this means that the chicken can be exposed to some moisture in the form of an anti-microbial solution (commonly water and chlorine) before being chilled primarily through blasts of cold air. Canadian and Western European producers have long practiced this technique, and retailers like Whole Foods have helped spread its importance in the US in the last decade due to perceived and proven benefits in the flavor and safety of the ready-to-cook product.
Immersion chilling involves chilling the poultry carcasses through immersion in a cold water solution containing one or more anti-microbial agents (again, usually chlorine). This technique is common practice in the US and has been criticized for the following reasons:
Should I Buy Chicken Labeled as Air Chilled?
To sum it up, some say that air chilled chicken is safer and more tasty, and others say it's the same. Air chilled chicken is not necessarily produced in a more ethical way or using fewer antibiotics: the label only applies to the way that the carcass is chilled. While air chilled chicken is not necessarily more expensive, my experience is that it usually costs more than its neighbors without the label. The best advice that I have (and the advice I will follow myself) is to try both kinds and make a decision based on personal taste.
Hopefully this information is helpful when it comes to picking out your poultry in the future! I'll finish things off with some additional "juicy tidbits" about related food labels that I stumbled across in my research: