Air Products claims to have cleared the air for meat processors

London - Liquid nitrogen (LIN) systems supplier Air Products says it has "dispelled the myth" that carbon dioxide offer advantages over LIN in cooling in meat mixing and forming applications.  The claim is based on a company-commissioned study of the effects of both cooling agents on shelf-life, colouration and dehydration.

According to Dr Chris Kennedy of Air Products, the findings show that use of liquid nitrogen for cooling assures product quality on a par with CO2 use. Meat processors, he said, can therefore choose freely between the two options without worrying about variations in end-product quality.

CO2’s ability to protect against spoilage in MAP packaging applications has led many processors to also use it to chill meats to increase its shelf-life. But the study showed that CO2 desorbs from meat very quickly after chilling, and so is unlikely to have any significant impact on shelf-life if it is not also used for subsequent MAP packaging.

Kennedy’s report also showed that meat placed in LIN or CO2 atmospheres could result in oxygen loss from its surface. This, he said, causes a reversion of the bright red oxymyoglobin pigment, which consumers often associated with freshness, to myoglobin – which has a deep purplish red colour. Although CO2 may lighten this colour slightly, the study proved that all colour changes were reversed when the meat was exposed to a normal atmosphere again.

Looking into dehydration rates, Dr Kennedy found that LIN could actually offer advantages over CO2. When using similar chilling equipment, liquid nitrogen was found to cause less dehydration than carbon dioxide because surface temperature is reduced more quickly.