If there is any theme worthy of emphasis to the extreme in this text, it must be safety. Lapses in food safety do not only adversely impact the health of consumers. Flagrant safety errors have and will ruin the reputation and financial health of the offending food company. Food safety violations have caused the demise of companies and prison sentences for culpable executives. Worse yet, highly publicized safety lapses indict an entire industry, implicating the innocent majority together with the single guilty company.
The combination of fruit raw materials, food ingredients, juice preparation and processing methods, provide the technologist with an practically infinite range of possible juice products varying in quality, price and value. The liquid nature of juices and the availability of many natural and manufactured juice constituents offer a blending opportunity not available to formulators working with solid foods. The versatility of juices plus the many mixing options are also a temptation to cut corners by economic adulteration.
The ease with which juices can be altered with sugar, water or inferior juices has and continues to attract unethical suppliers. Fortunately, advancements in analytical chemistry and instrumentation together with fruit and juice composition data banks make adulteration easier to detect (Nagy and Wade, 1995). Detection methods have more than kept up with adulteration schemes. Detection of doctored juices is expensive but fairly straightforward (Fry, Martin and Lees in Ashurst, 1995). Thus large international movements of juice are reasonably well monitored, although local, marginal producers continue to slip though the net.
Such unethical practices can also be dangerous, as there have been many tragic incidences of poisonous ingredients being added to juices. Fortunately, most countries now have food regulations and enforcement mechanisms that prevent such deception. Despite these efforts, another serious safety problem associated with juice consumption has arisen. Contamination of juices with pathogenic microorganisms such as E-coli O157 H7 and salmonella have caused numerous illnesses and some fatalities (Table 4.1). Although it appears that such incidences are increasing, in reality, surveillance and detection method are becoming much more sensitive. At the same time, outbreaks are becoming quite newsworthy. All reported cases of contamination by pathogenic microorganisms were due to fresh, unpasteurized juices. This is an increasingly popular segment of the juice industry, whose sales are now jeopardized by new regulations.
There is a curious irony in juice-induced food borne illnesses. Many common foods of plant and animal origin are much more hazardous and contain higher levels of more dangerous microbes than do fruits. However, if these foods are normally cooked before consumption, the inherently dangerous pathogens are eliminated. Fresh, unpasteurized juices receive no such treatment and, despite their health-promoting image, can harbour dangerous contaminants. Strategies to minimize such hazards are discussed in subsequent chapters.
Table 4.1: Fruit-associated food poisoning outbreaks*.
Juice Product (Year) |
Infectious Agent |
Sweet cider (1923) |
Salmonella typhi |
Orange juice (1944) |
S. typhi |
Orange juice (1962) |
Hepatitis A |
Orange juice (1966) |
Gastroenteritis agent |
Apple cider (1974) |
S. typhimurium |
Apple cider (1980) |
Enterotoxigenic E. coli |
Orange juice (1989) |
S. typhi |
Apple cider (1991) |
E.coli O157:H7 |
Orange juice (1992) |
Enterotoxigenic E. coli |
Apple cider (1993) |
E.coli O157:H7 |
Apple cider (1993) |
Cryptosporidium spp |
Carrot juice (1993) |
C. Botulinum |
Watermelon juice (1993) |
Salmonella spp. |
Orange juice (1994) |
Gastroenteritis agent |
Orange juice (1995) |
S. hartford, S. gaminera, S. rubislaw |
Apple juice (1996) |
E.coli O157:H7 |
Apple juice (1996) |
E.coli O157:H7 |
Apple juice (1996) |
Cryptosporidium parvum |
Apple cider (1997) |
E.coli O157 |
Orange juice (1998) |
Salmonella |
Apple cider (1998) |
E. coli O157:H7 |
Mamey juice (1999) |
Salmonella typhi |
Orange juice (1999) |
Salmonella enterica |
Orange juice (1999) |
Salmonella muenchen |
Apple cider (1999) |
E. coli O157:H7 |
Orange, grapefruit, lemonade (2000) |
Salmonella enterica |
*Adapted from Parish, 1997; Beuchat, 1998; Powell and Luedtke, 2000 and expanded
Acid fruit juices below pH 4.6 were once deemed a minor health threat due to the high acid. Furthermore, refrigeration temperatures (below 5ºC) represented an additional hurdle to pathogen growth, until the discovery that Listeria monocytogenes can grow down to 2ºC. When juice spoilage did occur, it was usually a reflection of the indigenous microflora, yeast, mould and lactic acid bacteria. Nonetheless, the emergence of hitherto unsuspected food pathogens with acid resistance combined with increase in susceptible individuals, immunocompromised, chronically ill, the very young and very elderly, has dramatically changed this picture. More stringent regulatory safeguards are now called for at all levels, i.e. provincial, national and international. Thus for safety and economic reasons commercial fruit juices are subject to strict regulatory control. Safety must always take precedent and strict limits on production, harvest, transportation, storage, manufacture, processing, labelling and distribution now exist. These are incorporated into Good Agricultural Practices (GAPs) and Good Manufacturing Practices (GMPs) with Hazard Analysis and Critical Control Point (HACCP) procedures being applied throughout the food chain. These will be emphasized as appropriate.
After safety concerns comes economic and quality considerations. A product can be perfectly safe and completely fraudulent. As the sale of a product labelled fruit juices may in fact consist of no or little actual fruit components. Thus the development of standards for fruit juices is incorporated into most country's regulatory codes. These regulations include the processing employed, the amount of fruit content required for various juice designations (Table 2.1), the soluble solids and acid levels, amount of added substances allowed such as sugar, acid, water, preservatives and reasonable sanitary standards.
In addition, grades may be assigned depending on the colour, flavour, consistency and absence of defects. Codex Alimentarius grades and standards are being promulgated and continue to be refined to provide a useful guide for standardizing national norms and facilitating intra and international trade (FAO, 2000b). In the matter of a large volume juice trade, specific standards are negotiated between major suppliers and users. For example, the Florida Department of Citrus, the state's industry controlling agency, has standards that exceed other norms and prohibit citrus juice manufacturing practices common in other regions (Florida Dept. Citrus, 2000).
In addition to existing international, national and local fruit/juice standards, detailed, industry-specific written quality specifications should be developed. Along with the safety and regulatory aspects, clear raw material specifications facilitate efficient processing (no surprises on the production floor) and uniform, consistent quality to the wholesale and retail purchasers. Reliability and trust throughout the food chain is essential. These standards should consist of physical, compositional, organoleptic specifications, as well as limits for microbial and chemical contaminants. Table 4.2 indicates some appropriate general specifications worth developing, if enforceable national regulations and/or controlling authorities do not already exist.
Analyses can readily detect trace amounts of pesticides, industrial chemicals and vanishing low numbers of pathogens, some with "zero" tolerance levels. Thus there has been a substantial increase in import denials and product recalls based on levels of contaminants, microbial and chemical, that were undetectable and unimportant a decade ago. The economic loss, not to mention the liability and poor publicity, is adequate incentive for juice processors to consistently take regulatory matters very seriously.
In industrialized nations and international trade, every step of juice manufacture from raw material cultivation through marketing is subjected to some type of regulatory control. Although some regulations can be onerous, burdensome, even unnecessary, there is a definite need to control food commerce items. The history of food control and the situations existing prior to development and enforcement of food laws surely justifies governmental oversight (Hui, Somogyi, et al., 1996a; FAO, 2000b and c). The two principal needs are:
Table 4.2: Some quality specifications for juice fruit.
Attribute |
Rationale |
Soluble solids (ºBrix) |
Defines juice strength |
Titratable acidity and pH |
Defines acid balance |
Colour |
Visual appeal |
Freedom from defects- decay, insects/damage, mechanical injury, etc |
Aesthetics, susceptibility to spoilage and contamination |
Maturity |
Optimum quality |
Size, shape and uniformity |
Ease of juicing |
Flavour |
Defines quality |
Absence of pathogens, chemicals and extraneous matter |
Defines safety |
Low microbial load |
Quality, shelf life |