GLASS CLOSURE EVALUATION: FACTORS AFFECTING VACUUM IN MODEL FOODS AND CLOSURE INTEGRITY OF EEASY LIDS

Abstract

Food preservation is a practice that has been believed to have aroused along with agriculture to sustain food supplies in periods of scarcity. Food packaging along with the basic function of containing the food has a major role in protecting the food against physical damage, microorganisms, tampering, and physiochemical degradation. It also helps to maintain product nutrition, safety, and shelf life. This project is focused on the factors that influence the integrity of a hermetic seal for glass containers with metal lids used for shelf-stable foods. The effects of water activity, hot-pack temperature, and headspace on the vacuum measurements in glass closures were evaluated. Tests were performed in triplicates with glucose solutions as model foods ranging in water activity from 0.6 to 1, hot-pack temperature from 170°F to 200 °F and headspace of 6% and 10%. Results indicated that vacuum levels decreased with lower hot-pack temperatures, reduced water activity values, and increased headspace volume. There was at least a 1.5-fold increase in vacuum levels after steam flushing the headspace in the jars compared to just hot packing. The evaluation of closure integrity of tomato sauce jars when using the new EEasy Lids was tested by measuring vacuum, removal torque, security and pull-up values. EEasy Lids is a major innovation in the lid industry which reduces the torque needed to open the glass jar significantly. Compared with standard lug lids presently in the market, the EEasy lids needed a removal torque in the range of 11.5-15 lb-in compared to 20-28 lb-in for standard lids.