Inactivation of Campylobacter jejuni by high hydrostatic pressure

Abstract

Aims: To investigate the response of Campylobacter jejuni ATCC 35919 and 35921 to high pressure processing (HPP) while suspended in microbiological media and various food systems. Methods and Results: Campylobacter jejuni 35919 and 35921 were subjected to 10-min pressure treatments between 100 and 400 MPa at 25°C suspended in Bolton broth, phosphate buffer (0AE2 M M, pH 7AE3), ultra-high temperature (UHT) whole milk, UHT skim milk, soya milk and chicken pureé. The survivability of C. jejuni was further investigated by inoculated pack studies. HPP at 300-325 MPa for 10 min at 25°C was sufficient to reduce viable numbers of both strains to below detectable levels when cells were pressurized in Bolton broth or phosphate buffer. All food products examined offered a protective effect in that an additional 50-75 MPa was required to achieve similar levels of inactivation when compared with broth and buffer. Inoculated pack studies showed that the survivability of C. jejuni following pressurization improved with decreasing post-treatment storage temperature. Significance and Impact of the Study: These data demonstrated that HPP at levels of £400 MPa, can inactivate C. jejuni in both model and food systems.

Baroprotection of vegetative bacteria by milk constituents: A study of Listeria innocua

“…Data presented in this communication indicate a strong protective effect of milk constituents against HP-induced inactivation of L. innocua 4202; other authors have previously commented on the strong protection milk confers to other microorganisms against HP (Dogan & Erkmen, 2004;Garcia-Graells, Masschalck, & Michiels, 1999;Hauben et al, 1998;Solomon & Hoover, 2004;Styles et al, 1991). However, little was known previously about either the specific protective agents in milk or the mechanisms by which they protect.…”

Design and evaluation of a high hydrostatic pressure combined process for pasteurization of liquid whole egg

“…However, complex food matrices, like LWE, can provide a protective effect, inhibiting the HHP inactivation of contaminating bacteria that are likely to be inactivated at moderate pressures of 200 to 500 MPa (Solomon & Hoover, 2004). Treatments of 200 to 350 MPa for minutes hardly affect microbial lethality, and pressures of 300 to 450 MPa applied for 5-15 min, are required to reduce more than 2 Log 10 the population of microorganisms such as L. innocua, E. coli and Salmonella Enteritidis in egg products (Isiker, Gurakan, & Bayindirli, 2003;Lee, Heinz, & Knorr, 2003;Ponce, Pla, Mor-Mur, Gervilla & Guamis, 1998;Ponce, Pla, Sendra, Guamis & Mor-Mur, 1998).…”

Modeling the pressure inactivation dynamics of Escherichia coli

“…High-pressure treatment of food, which can inactivate microorganisms and detrimental enzymes with retention of taste, texture, color, or nutrients, has an advantage over heat treatment which may cause deterioration of beneficial food components. Most of the common bacterial food-borne pathogens such as Campylobacter jejuni (2), Salmonella (3,4), Vibrio spp. (5), Escherichia coli O157:H7 (4,6), Yersinia enterocolitica (4,7), and Listeria monocytogenes (4)(5)(6)8) have been investigated in a variety of food systems and buffers, at various temperatures and for various pressureholding times.…”