Investigations on the Ingress of Process Water During the Pasteurization of Beverage Containers

When heat treating (pasteurizing) bottled or canned, carbonated beverages, such as beer and beer products or soft drinks, to reduce and/or kill any potential product spoilage organisms in their respective container, usually large tunnel pasteurizers are used. These machines spray hot water over the containers to ultimately reach a sufficient core temperature in the beverage container. Studies have shown that this process water contains a high count of diverse microorganisms. Reports from the industry and proven incidents imply that in very rare cases this process water and the related ingress of microorganisms can be detected in microbiological quality control of the product. To this date no investigations have proven or disproven these rare events. This study aims to collect evidence on the likelihood of these events occurring during large scale pasteurization. The possibility of an exchange with the environment during pasteurization could be proven by loss of CO2 throughout the process. This only occurred in bottles closed with crown corks, not in swing tops and cans. An ingress of process water could not be proven in the presented study but evidence was found that crown cork bottles are also the most likely container type for such a phenomenon to happen.