ABSTRACT
CONTENTS 10.1 Microbiology of Fresh-Cut Produce.............................................................................. 213
10.1.1 Introduction ......................................................................................................... 213 10.1.2 Food Poisoning Linked to Fresh-Cut Products .............................................. 214 10.1.3 Human Pathogens of Concern.......................................................................... 215
10.1.3.1 Listeria monocytogenes .......................................................................... 215 10.1.3.2 Escherichia coli 0157:H7........................................................................ 215 10.1.3.3 Clostridium botulinum .......................................................................... 215 10.1.3.4 Salmonella .............................................................................................. 216 10.1.3.5 Viruses and Protozoa.......................................................................... 216
10.2 Implications of Field Production ................................................................................... 217 10.2.1 Sources of Contamination.................................................................................. 217 10.2.2 Implications of Production Systems................................................................. 218 10.2.3 Irrigation and Flooding...................................................................................... 219 10.2.4 Training of Field Workers ................................................................................. 219 10.2.5 Implications of Globalization............................................................................ 220 10.2.6 Field Production as a Critical Control Point for Contamination................. 220
10.3 Implications of Minimal Processing.............................................................................. 221 10.3.1 Cutting and Peeling............................................................................................ 221 10.3.2 Antimicrobial Treatments .................................................................................. 221
10.4 Implications of Modified Atmospheres........................................................................ 222 10.5 Storage Temperature ....................................................................................................... 223 10.6 HACCP and Safety Assurance ...................................................................................... 224 10.7 Challenges and Research Needs.................................................................................... 225 10.8 Conclusions....................................................................................................................... 226 References.................................................................................................................................... 226
10.1.1 Introduction
Fresh-cut products provide substrates and environmental conditions, which support the survival and growth of microorganisms. Minimal processing treatments such as peeling and slicing provide a potentially richer source of nutrients than intact produce
and
(Barry-Ryan and O’Beirne, 1998, 2000; Brackett, 1994). This, combined with high Aw and close to neutral (vegetables) or low acid (many fruits) tissue pH, facilitate microbial growth (Beuchat, 1996). These products harbor large and diverse populations of microorganisms, and counts of
105-107 CFU=g are frequently present. Most bacteria present are Gram-negative rods, predominantly Pseudomonas, Enterobacter, or Erwinia species (Brocklehurst et al., 1987; Garg et al., 1990; Magnuson et al., 1990; Manvell and Ackland, 1986; Marchetti et al., 1992; Nguyen-the and Prunier, 1989). Product type, production history, and storage conditions are major factors determining what organisms are present and their populations. Lactic acid bacteria have been detected in mixed salads and grated carrots, and may predominate in salads when held at severe abuse (308C) temperatures (Manvell and Ackland, 1986). Yeasts commonly isolated include Cryptococcus, Rhodotorula, and Candida (Brackett, 1994). Webb and Mundt (1978) surveyed 14 different vegetables for molds. The most commonly isolated genera were Aureobasidium, Fusarium, Mucor, Phoma, Rhizopus, and Penicillium.
