Novel MAP applications for fresh-prepared produce 197 produce. Potential applications of high O2 MAP to chilled combination food items(e.g. chilled ready meals, pizzas, kebabs, etc. )have been the subject of recent research(Day, 2001b), but are outside the scope of this chapter 10.4.1 Safety A specific guideline document on The safe application of oxygen enriched atmospheres when packaging food has been published an nd is publicly availa (BCGA, 1998). This document contains clear and concise advice and commendations on how to control safely the hazards of utilising O2-rich gas mixtures for the map of food Food companies and related industries (e.g. gas companies and MAP machinery manufacturers) are strongly encouraged to purchase this safety guidelines document and to follow closely the advice and recommendations given before undertaking any pre-commercial trials using high O2 MAP. Further advice and help on the safety aspects of high O2 MAP can be sought from qualified gas safety engineers and the bcga 10.4.2 Optimal gas levels Based on CCFRA's practical experimental trials, the recommended optimal headspace gas levels immediately after fresh prepared produce package sealing 80-95%O2/5-20%N After package sealing, headspace O2 levels will decline whereas CO2 levels will increase during chilled storage due to the intrinsic respiratory nature of fresh prepared produce. As previously explained, the levels of O2 and cO2 established within hermetically sealed packs of produce during chilled storage are influenced by numerous variables, i.e. the intrinsic produce respiration rate (which itself is affected by temperature; atmospheric composition; produce type variety, cultivar and maturity; and severity of preparation); packaging film permeability; pack volume, surface area and fill weight; produce volume/gas volume ratio and degree of illumination(Kader et al, 1989; Day, 1994; O Beirne, 1999) To maximise the benefits of high O MAP, it is desirable to maintain headspace levels of O2 >40% and CO2 in the range of 10-25% during the chilled shelf-life of the product. This can be achieved by lowering the temperature of storage, by selecting produce having a lower intrinsic respiration rate, by minimising cut surface tissue damage, by reducing the produce volume/ gas volume ratio by either decreasing the pack fill weight or increasing the pack headspace volume, by using a packaging film which can maintain high levels of O2 whilst selectively allowing excess CO2 to escape, or by incorporating an innovative active packaging sachet that can adsorb excess CO2 and emit an equal volume of O2(McGrath, 2000)produce. Potential applications of high O2 MAP to chilled combination food items (e.g. chilled ready meals, pizzas, kebabs, etc.) have been the subject of recent research (Day, 2001b), but are outside the scope of this chapter. 10.4.1 Safety A specific guideline document on The safe application of oxygen enriched atmospheres when packaging food has been published and is publicly available (BCGA, 1998). This document contains clear and concise advice and recommendations on how to control safely the hazards of utilising O2-rich gas mixtures for the MAP of food. Food companies and related industries (e.g. gas companies and MAP machinery manufacturers) are strongly encouraged to purchase this safety guidelines document and to follow closely the advice and recommendations given before undertaking any pre-commercial trials using high O2 MAP. Further advice and help on the safety aspects of high O2 MAP can be sought from qualified gas safety engineers and the BCGA. 10.4.2 Optimal gas levels Based on CCFRA’s practical experimental trials, the recommended optimal headspace gas levels immediately after fresh prepared produce package sealing are: 80-95% O2/5–20% N2 After package sealing, headspace O2 levels will decline whereas CO2 levels will increase during chilled storage due to the intrinsic respiratory nature of fresh prepared produce. As previously explained, the levels of O2 and CO2 established within hermetically sealed packs of produce during chilled storage are influenced by numerous variables, i.e. the intrinsic produce respiration rate (which itself is affected by temperature; atmospheric composition; produce type, variety, cultivar and maturity; and severity of preparation); packaging film permeability; pack volume, surface area and fill weight; produce volume/gas volume ratio and degree of illumination (Kader et al., 1989; Day, 1994; O’Beirne, 1999). To maximise the benefits of high O2 MAP, it is desirable to maintain headspace levels of O2 > 40% and CO2 in the range of 10–25% during the chilled shelf-life of the product. This can be achieved by lowering the temperature of storage, by selecting produce having a lower intrinsic respiration rate, by minimising cut surface tissue damage, by reducing the produce volume/ gas volume ratio by either decreasing the pack fill weight or increasing the pack headspace volume, by using a packaging film which can maintain high levels of O2 whilst selectively allowing excess CO2 to escape, or by incorporating an innovative active packaging sachet that can adsorb excess CO2 and emit an equal volume of O2 (McGrath, 2000). Novel MAP applications for fresh-prepared produce 197