Clostridium botulinum and Acid Foods

Abstract

Outbreaks of botulism involving acid foods are rare. Of the 722 total botulism outbreaks reported from 1899 to 1975, only 34 (4.7%) involved acid foods. Home-canned acid foods were implicated in 34 of the 35 acid food outbreaks. Clostridium botulinum cannot grow at a pH of ⩽ 4.6; therefore, for a botulism hazard to exist in an acid food, a contamination with other microorganisms due to a process delivery failure and/or post-process contamination, (c) favorable composition of the food and storage conditions which are particularly conducive to C. botulinum growth and toxin production, and (d) metabiosis. The way each factor affects the botulism hazard in acid foods is discussed in this report. An acid food is safe from C. botulinum if the heat process kills all organisms capable of growth at a pH of ⩽4.6 and there is no post-process contamination.

Growth and toxin formation by Clostridium botulinum at low pH values

“…botulinum will not grow and produce toxin in foods at pH 4.6 or below. Published reports of strains growing at pH values below 4.5 have been reviewed critically by Ingram & Robinson (1951), Baird-Parker (1969) and Odlaug & Pflug (1978). Growth of CZ.…”

Clostridium botulinumandClostridium tetani

“…This grouping is also supported by metabolic and structural properties including nutritional requirements (Belokopytov et al 1982;Kindler et al 1956;Mager et al 1954;Malizio et al 1993;Patterson-Curtis and Johnson 1992;Whitmer and Johnson 1988), resistance to salt and acidity and other environmental and food components (Anniballi et al 2002;Glass and Johnson 2001;Hammer and Johnson 1988;Hutchinson 1992;Odlaug and Pflug 1978;Ohye and Scott 1957;Raatjes and Smelt 1979;Lynt et al 1982;Sugiyama and Sofos 1988;Townsend et al 1954), spore heat resistance and germination properties (Broussolle et al 2002;Ito et al 1968;Lund and Peck 2000;Lynt et al 1975;Scott and Bernard 1982;Setlow and Johnson 2001), tolerance to air (Meyer 1924;Whiting and Naftulin 1992), minimum growth temperature (Eklund et al 1976;Smith and Sugiyama 1988), endproduct formation (Mead 1971;Moore et al 1966;Moss et al 1970Moss et al , 1980Oguma et al 1986;Smith and Sugiyama 1988), and toxin regulation. The four groups also have distinctive surface antigen relationships (Batty and Walker 1966;Hatheway 1983, 1984a, b;Lynt et al 1967;Solomon et al 1969Solomon et al , 1971…”

Heat transfer phenomena during thermal processing of liquid particulate mixtures—A review

“…This prompts the need for improving thermal processing technology further through constant innovations in the design of retorts and data collection and analysis methodologies. Larousse and Brown, 1996;Odlaug and Pflug, 1997). Stumbo et al (1975) Small cans (54.0 mm x 57.2 mm): Odlaug and Pflug (1997) 3.3 -3.5 F 10/195 = 1.0 min Nelson and Tressler (1980) 3.5 -4.0 F 10/195 = 16 -23 min Barrett et al (2004)  A rigid thermocouple is attached to the particlecenter or the slowest point of heating.…”

“…Thus, for a minimal process, heating low-acid foods at high temperatures under sterilization conditions is necessary, while a lower level of thermal treatment at pasteurization conditions is enough for high-acid foods. Additional details about heat resistance of microbes, level of pH and reference temperatures involved are available in literature (Ball and Olson, 1957;Breidt et al, 2007;Brown, 2000;Larousse and Brown, 1996;Montville and Sapers, 1981;Odlaug and Pflug, 1997;Stumbo, 1973).…”