barbecue as a cooking method

Barbecue as a cooking method.

Cooking food, particularly meat, is used to make it suitable for human consumption by killing bacteria and improving its aesthetic appeal. The Maillard Reaction[1] that occurs during cooking makes barbecue an extremely popular method of cooking meat due to the effect it has in transforming the flavour. Whilst this increases the aesthetic appeal of food there is evidence that grilling as a cooking processes can lead to the production of carcinogens such as acrylamide (Stadler et al., 2002, p.449), heterocyclic aromatic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) (Viegas et al., 2012). Despite this evidence circulating in the media (Kirby, 2017) Jägerstad and Skog (2005, p.156) argue that there is insufficient evidence that these compounds directly cause cancer in humans through dietary intake, as most studies used concentrations well in excess of a human diet and used tobacco smoke and environmental exposure as data sources, not cooked food. Despite the lack of conclusive evidence, the issue becomes relevant to barbecue as studies have found that grilled barbecue meat is susceptible to higher levels of HCAs and PAHs, due to the combustion of rendered fat being re-absorbed into the food (Oz and Yuzer, 2016, p.59, Aaslyng et al., 2013, p.85 and Rose et al., 2015, p.1). Methods of reducing levels of PAHs and HCAs in barbecue food include decreasing the cooking period, reducing the distance of food from the heat source, removing the ability of fat to drop onto the heat source and the use of clean burning hardwood or coconut shell charcoal (Rose et al., 2015, p.9, Oz and Yuzer, 2016, p.65, Jägerstad and Skog, 2005, p.167-168 and Viegas et al., 2012, p.2128). The level of HCAs and PAHs is also reduced by the addition of ingredients, usually as a marinade, containing any of the following: garlic, onion powder, lemon juice, beer, red wine, virgin olive oil, apple, lemongrass oil, clove bud oil, rosemary and chilli pepper (Gibis, 2007, p.10240, Melo et al., 2008, p.10625, Persson et al., 2003, p.1587, Rounds et al., 2012, p.3792, Puangsombat and Smith, 2010, p.40, and Oz and Kaya, 2011, p.806). In addition to these ingredients already being used for culinary purposes in barbecue food, American barbecue is characterised by low and slow, indirect methods of cooking, the use of rubs containing antioxidants (as above) and when grilling is done most have a preference for less well done grilled red meat and the use of marinades containing the antioxidants listed above. So, whilst a sustainability consideration from a health point of view, methods that to some extent mitigate sources of HCAs and PAHs are already being used.

In addition to HCAs and PAHs, other compounds harmful to health such as VOCs[2] and carbonyls[3] have been found in foods cooked over charcoal (Kabir et al., 2010, p.492). However, in this study there was only one compound in one sample (out of a total of sixteen) that exceeded permissible levels.[4] It also did not specify the source country, manufacturing method or raw material, all of which determine the VOC content, the latter of which the study acknowledges can contain “furniture or flooring materials containing various pollutants…coated with paint…as a source of VOCs when combusted” (Kabir et al., 2010, p.498). A good quality charcoal with a high fixed carbon content does not release any VOCs on combustion.

[1] A chemical reaction between amino acids and sugar usually requiring heat, that gives each food its unique flavour and distinctive brown appearance (Hodge, 1953).

[2] Including benzene and tolulene.

[3] Such as formaldehyde.

[4] This was formaldehyde, which marginally exceeded the Permissible Exposure Limit (PEL), set by the US Occupational Safety and Health Administration (OSHA), by 0.008ppm (sample contained 2.008ppm, where the OSHA PEL is 2.000ppm).