ABSTRACT
CONTENTS 9.1 Introduction ........................................................................................................................ 193 9.2 General Effects of MA and CA on Decay of Horticultural Commodities ................ 194 9.3 Effects of MA and CA on Specific Plant Pathogens ..................................................... 197 9.4 Specific Effects of Low O2 and High CO2...................................................................... 201 9.5 Combined Effects of Low O2 and Elevated CO2 Atmospheres.................................. 203 9.6 Effects of Carbon Monoxide............................................................................................. 204 9.7 Effects of Superatmospheric Oxygen (High O2) Atmospheres................................... 206 9.8 Conclusions......................................................................................................................... 207 9.9 Future Research.................................................................................................................. 207 References.................................................................................................................................... 208
Controlled atmosphere (CA) and modified atmosphere (MA) technologies are widely used commercially for storage, transport, and packaging of several horticultural commodities (Ben-Yehoshua et al., 2005). These technologies have many advantages including delay of ripening and senescence, control of some physiological and plant pathological diseases, and control of some insects (Yahia, 1998, 2007, 2006). CA and MA are known to inhibit a wide range of plant pathogens either directly or indirectly (El-Goorani and Sommer, 1981). Atmospheres containing about 2-5 kPa O2, commonly used in CA storage, suppress decay indirectly by acting upon host resistance, rather than directly on the pathogen since most fungi grow under these conditions (Barkai-Golan, 2001). CA and MA maintain fruit firmness and thus delay or prevent penetration by microorganisms. Atmospheric levels that act directly on microorganisms by inhibiting them and thus reducing decay are generally <1 kPa O2 and >10 kPa CO2 (Kader and Ben-Yehoshua, 2000). For this reason, most CA and MA commercial applications effect decay indirectly (Ben-Yehoshua et al., 2005). In recent years, safety of minimally processed foods has become an important issue especially in the interaction of MA with the growth of bacterial pathogens that cause illness or death in humans (Farber, 1991; Phillips, 1996; Werner and Hotchkiss, 2006); this subject is dealt with in detail in Chapter 10. In this chapter, we review the effects of CA and MA in relation to spoilage of horticultural commodities by decay organisms, as impacted by concentration of CO2 and O2 and some other gases and their effect on produce quality and microbial growth.
