Oxygen, ethylene and other scavengers 25 Table 3.1 Effects of oxygen scavengers on foods(Abe, 1994; Smith et al, 1990) Effect Typical application Fresh taste and aroma arious food items, coffee, tea lusts, cheese, processed Nuts, fried foods, processed meat, whole er produc duration Processed meat, green noodle, herbs, tea, ← Insect damage Beans, grain, herbs, spices Maintaining nutritional value All kinds of foods products were packaged in air and air with an Ageless Ss oxygen absorber and stored at 4, 12 and 25C. Toxin was not detected in any raw product throughout stor 8 days). The absence of toxigenesis was attributed to the low pH (4.1 4.3)due mainly to the growth of lactic acid bacteria. Whiting and naftulil (1992) showed that controlling the pH and NaCl concentration of the food product is an important factor in controlling growth of C. botulinum under low oxygen concentrations. When oxygen absorbers are used, challenge studies should be done to investigate if C. botulinum is able to grow. An overview of the effects of oxygen scavengers and their most important food applications is shown in Table 3.1 3.3 Selecting the right type of oxygen scavenger Oxygen scavengers must satisfy several requirements: they must 1. be harmless to the human body. Though the oxygen scavengers themselves are neither food nor food additives, they are placed together with food in a package, and there is therefore the possibility of accidental intake 2. absorb oxygen at an appropriate rate. If the reaction is too fast, there will be a loss of oxygen absorption capacity during introduction into the package. If it is too slow, the food will not be adequately protected from oxygen 3. not produce toxic substances or unfavourable gas or odour. performance 5. absorb a large amount of oxygen 6. be economically priced(Nakamura and Hoshino, 1983: Abe, 1994; Rooney An appropriate oxygen scavenger is chosen depending on the O2-level in the headspace, how much oxygen is trapped in the food initially and the amount ofproducts were packaged in air and air with an AgelessÕ SS oxygen absorber and stored at 4, 12 and 25ºC. Toxin was not detected in any raw product throughout storage (28 days). The absence of toxigenesis was attributed to the low pH (4.1– 4.3) due mainly to the growth of lactic acid bacteria. Whiting and Naftulin (1992) showed that controlling the pH and NaCl concentration of the food product is an important factor in controlling growth of C. botulinum under low oxygen concentrations. When oxygen absorbers are used, challenge studies should be done to investigate if C. botulinum is able to grow. An overview of the effects of oxygen scavengers and their most important food applications is shown in Table 3.1. 3.3 Selecting the right type of oxygen scavenger Oxygen scavengers must satisfy several requirements: they must 1. be harmless to the human body. Though the oxygen scavengers themselves are neither food nor food additives, they are placed together with food in a package, and there is therefore the possibility of accidental intake by consumers. 2. absorb oxygen at an appropriate rate. If the reaction is too fast, there will be a loss of oxygen absorption capacity during introduction into the package. If it is too slow, the food will not be adequately protected from oxygen damage. 3. not produce toxic substances or unfavourable gas or odour. 4. be compact in size and are expected to show a constant quality and performance. 5. absorb a large amount of oxygen. 6. be economically priced (Nakamura and Hoshino, 1983; Abe, 1994; Rooney, 1995). An appropriate oxygen scavenger is chosen depending on the O2-level in the headspace, how much oxygen is trapped in the food initially and the amount of Table 3.1 Effects of oxygen scavengers on foods (Abe, 1994; Smith et al., 1990) Effect Typical application Fresh taste and aroma Various food items, coffee, tea $ Mould growth Bakery products, cheese, processed seafood, pasta $ Rancidity Nuts, fried foods, processed meat, whole milk powder product $ Discolouration Processed meat, green noodle, herbs, tea, dried vegetables $ Insect damage Beans, grain, herbs, spices Maintaining nutritional value All kinds of foods Oxygen, ethylene and other scavengers 25