manufacturers to ensure that the microbial safety of food products would not decrease with changes in formulation to reduce salt (Advisory Committee on the Microbiological Safety of Food, 2008).
There is also evidence suggesting that reductions in salt might result in greater risk of toxin formation by Clostridium botulinum (the organism responsible for botulism) in certain foods if additional hurdles are not incorporated. This is particularly the case for foods that have not been heated sufficiently to inactivate C. botulinum spores and have little oxygen present. Processed cheese (Glass and Doyle, 2005; Karahadian et al., 1985), meat products (Barbut et al., 1986), and sous vide products (products that are prepared in vacuum-sealed plastic pouches and heated at low temperatures for long times1) have been recognized as having potential for C. botulinum control problems when sodium is reduced (Simpson et al., 1995). For example, decreases in salt content from 1.5 to 1.0 percent by weight greatly reduced the time needed for C. botulinum type A and B spores to produce toxins in sous vide spaghetti and meat sauce products when stored at typical refrigeration temperatures. At salt concentrations at or above 1.5 percent, no toxin production was detected from the inoculated products during the 42-day storage period, while at 1.0 percent salt addition, toxins were produced within 21 days (Simpson et al., 1995). Similarly, turkey frankfurters inoculated with C. botulinum and held at 27°C showed more rapid toxin production when salt content was 2.5 percent than when it was 4.0 percent (Barbut et al., 1986).
In addition to C. botulinum and L. monocytogenes, the growth of other foodborne pathogens may be more rapid in foods with reduced contents of salt and other sodium-containing preservatives. These pathogens include Bacillus cereus, Staphylococcus aureus, Yersinia enterocolitica, Aeromonas hydrophila, Clostridium perfringens, and Arcobacter (D’Sa and Harrison, 2005; Reddy and Marth, 1991; Stringer and Pin, 2005).
While the pathogens described above must be taken into account, product developers and researchers have been able to accomplish sodium reductions even in products such as processed cheese and processed meats (Reddy and Marth, 1991). A number of hurdles can be added or increased when sodium is reduced to ensure that a product’s safety is maintained. Examples of additional hurdles are listed in Table 4-2. This list includes a number of emerging technologies (e.g., high-pressure processing, electron beam irradiation) that may have wider applications in the future.
Compounds, such as potassium chloride (Barbut et al., 1986) and mixtures of potassium lactate and sodium diacetate (Devlieghere et al., 2009), that might be used to replace salt and other sodium-containing pre-
Available online: http://amath.colorado.edu/~baldwind/sous-vide.html (accessed October 25, 2009).