Hygiene by Design

Advanced Dairy Science and Technology

Volumn , Issue , 2008, Pages 75-120

  Mostert, J Ferdie ^a   Buys, Elna M ^b  

^a AGRICULTURAL RESEARCH COUNCIL   (South Africa)

^b UNIVERSITY OF PRETORIA   (South Africa)

Author keywords

Biofilms; Clean room design; Contamination; Hygienic equipment design; Sanitization

Indexed keywords

EID: 84886014223     PISSN: None     EISSN: None     Source Type: Book    
DOI: 10.1002/9780470697634.ch3     Document Type: Chapter

References (134)

1. Al-Dagal, M. and Fung, D.Y.C. (1990) Aeromicrobiology-a review. CRC Critical Reviews of Food Science and Nutrition 29, 333-340.
2. Anon. (1988) Recommended guidelines for controlling environmental contamination in dairy plants. Dairy and Food Sanitation 8, 52-56.
3. Anon. (1993) Council directive 93/43/EEC of 14 June 1993 on the hygiene of foodstuffs. Official Journal of European Communities L175, 1-11.
4. Anon. (1995) HACCP and the Lumac Solution. Lumac, Landgraaf, Netherlands.
5. Anon. (1997) Recommended international code of practice: General principles of food hygiene. In: Codex Alimentarius Commission Food Hygiene Basic Texts: CAC/RCP1-1969 Rev 3. Food and Agriculture Organization of the United Nations, World Health Organization, Rome.
6. Anon. (2005) The never ending war on pests in the food sector. International Food Hygiene 16, 5, 7.
7. Arnould, P. and Guichard, L. (1999) Disinfection of dairy factories using fumigation. Latte 24, 44-46.
8. Austin, J.W. and Bergeron, G. (1995) Development of bacterial biofilms in dairy processing lines. Journal of Dairy Research 62, 509-519.
9. Bell, C. H. (2003) Pest control: insects and mites. In: Lelieveld, H.L.M., Mostert, M.A., Holah, J. and White, B. (eds.) Hygiene in Food Processing, Woodhead, Cambridge, pp. 335-379.
10. Bénézech, T., Lelievre, C., Membre, J.M., Viet, A.-F. and Faille, C. (2002) A new test method for in-place cleanability of food processing equipment. Journal of Food Engineering, 54, 7-15.
11. Brocklehurst, T.F., Zaman-Wong, C.M. and Lund, B.M. (1987) A note on the microbiology of retail packs of prepared salad vegetables. Journal of Applied Bacteriology 63, 409-415.
12. Brown, K.L. (2003) Control of airborne contamination. In: Lelieveld, H.L.M., Mostert, M.A., Holah, J. and White, B. (eds.) Hygiene in Food Processing, Woodhead, Cambridge, pp. 106-121.
13. Brown, K.L., Wileman, R. and Smith, J. (2002) Airborne Contamination Risk from Food Production Personnel. R&R Report 163. Campden and Chorleywood Food Research Association, Chipping Campden, UK.
14. BSI (1991) Methods of Microbiological Examination for Dairy Purpose, BS 4285: Part 4. British Standards Institution, London.
15. Bylund, G. (1995 In: Dairy Processing Handbook. Tetra Pak Processing Systems A/B, Lund, Sweden.
16. CAC/RCP (2004) Code of Hygiene Practice for Milk and Milk Products. CAC/RCP 57, pp. 1-40.
17. Carey, N.R., Murphy, S.C., Zadoks, R.N. and Boor, K.J. (2005) Shelf lives of pasteurized fluid milk products in New York State: a ten year study. Food Protection Trends 25, 102-113.
18. Carpentier, B., Wong, A.C.L. and Cerf, O. (1998) In: Biofilms on Dairy Plant Surfaces: What's New? Bulletin 329, pp. 32-35. International Dairy Federation, Brussels, Belgium.
19. Chamberlain, C.J. (1983) Opportunities for ultrasonics. Food Processing 52, 35-37.
20. Charlton, B.R., Kinde, H. and Jensen, L.H. (1990) Environmental survey for Listeria species in California milk processing plants. Journal of Food Protection 53, 198-201.
21. Chmielewski, R.A.N. and Frank, J.F. (2003) Biofilm formation and control in food processing facilities. Comprehensive Reviews in Food Science and Food Safety 2, 22-32.
22. Clesceri, L.S., Greenberg, A.E. and Trussell, R.R. (1989) Standard Methods for the Examination of Water and Waste Water, 17th edn, pp. 9.1-9.227. APHA, Washington, DC.
23. Cocker, R. (2003) The regulation of hygiene in food processing: an introduction. In: Lelieveld, H.L.M., Mostert, M.A., Holah, J. and White, B. (eds.) Hygiene in Food Processing, pp. 3-18. Woodhead, Cambridge.
24. Costerton, J.W., Lewandowski, Z., Caldwell, D.E., Korber, D.R. and Lappin-Scott, H.M. (1995) Microbial biofilms. Annual Review of Microbiology 49, 711-745.
25. Den Aantrekker, E.D., Boom, R.M., Zwietering, M.H. and Von Schothorst, M. (2003) Quantifying recontamination through factory environments-a review. International Journal of Food Microbiology 80, 117-130.
26. Dunsmore, D.G. (1983) The incidence and implications of residues of detergents and sanitizers in dairy products. Residue Reviews 86, 1-63.
27. Dunsmore, D.G., Thomson, M.A. and Murray, G. (1981a) Bacteriological control of food equipment surfaces by cleaning systems. III. Complementary cleaning. Journal of Food Protection 44, 100-108.
28. Dunsmore, D.G., Twomey, A., Whittlestone, W.G. and Morgan, H.W. (1981b) Design and performance of systems for cleaning product-contact surfaces of food equipment: a review. Journal of Food Protection 44, 220-240.
29. El-Shenawy, M.A. (1998) Sources of Listeria spp. in domestic food processing environment. International Journal of Environmental Health Research 8, 241-251.
30. Evans, J.A., Russell, S.L., James, C. and Corry, J.E.L. (2004) Microbial contamination of food refrigeration equipment. Journal of Food Engineering 62, 225-232.
31. Fadda, S., Aymerich, T., Hugas, M. and Garriga, M. (2005) Use of a GMP/GHP HACCP checklist to evaluate the hygienic status of traditional dry sausage workshops. Food Protection Trends 25, 522-530.
32. Fatemi, P. and Frank, J.F. (1999) Inactivation of Listeria monocytogenes/Pseudomonas biofilms by peracid sanitizers. Journal of Food Protection 62, 761-765.
33. Floh, R. (1993) Automatic recirculation cleaning in the 90's. Dairy Food and Environmental Sanitation 13, 216-219.
34. Frank, J.F. (2000) Microbial attachment to food and food contact surfaces. Advances in Food and Nutrition Research 43, 319-370.
35. Fricker, C. (1993) Water supplies: Microbiological analysis. In: Macrae, R., Robinson, R.K. and Sadler, M.J. (eds.) Encyclopaedia of Food Science, Food Technology and Nutrition, pp. 4859-4861. Academic Press, London.
36. Frontini, S. (2000) Clean air during production. Latte 25, 28-34.
37. Gibson, H., Taylor, J.H., Hall, K.E. and Holah, J.T. (1999) Effectiveness of cleaning techniques used in the food industry in terms of the removal of bacterial biofilms. Journal of Applied Microbiology 87, 41-48.
38. Graβhoff, A. (1997) Cleaning of heat treatment equipment. In: Fouling and Cleaning of Heat Treatment Equipment-a Monograph. Bulletin 328, pp. 32-44. International Dairy Federation, Brussels.
39. Guyader, P. (1995) Contamination of products: be careful with compressed air. Dairy Science Abstracts 58, 208.
40. Hale, N., Bertsch, R., Barnett, J. and Duddelston, W.L. (2003) Sources of wastage in the dairy industry. In: Guide for Dairy Managers on Wastage Prevention in Dairy Plants, Bulletin 328, pp. 7-30. International Dairy Federation, Brussels.
41. Hall-Stoodley, L., Costerton, J.W. and Stoodley, P. (2004) Bacterial biofilms: from the natural environment to infectious diseases. Nature Reviews Microbiology 2, 95-108.
42. Hall-Stoodley, L. and Stoodley, P. (2005) Biofilm formation and dispersal and the transmission of human pathogens. Trends in Microbiology 13, 7-10.
43. Harrigan, W.F. and McCance, M.E. (1976) Laboratory Methods in Food and Dairy Microbiology, 2nd edn. Academic Press, London.
44. Hedberg, C.W, Korlath, J.A., D'Aoust, J.-Y, White, K.E., Schell, W.L., Miller, M.R., Cameron, D.N., MacDonald, K.I. and Osterholm, M.T. (1992) A multistate outbreak of Salmonella javiana and Salmonella oranienburg infections due to consumption of contaminated cheese. JAMA 268, 3203-3207.
45. Hedrick, T.I. (1975) Engineering and science of aeromicrobiological contamination control in dairy plants. Chemistry and Industry 20, 868-872.
46. Hedrick, T.I. and Heldman, D.R. (1969) Air quality in fluid and manufactured milk products plants. Journal of Milk and Food Technology 32, 265-269.
47. Heldman, D.R. and Hedrick, T.I. (1971) Air-borne contamination control in food processing plants. Research Bulletin 33, pp. 76-77. Michigan State University, Agricultural Experiment Station, East Lansing, MI.
48. Heldman, D.R., Hedrick, T.I. and Hall, C.W. (1965) Sources of airborne microorganisms in food processing areas-drains. Journal of Milk and Food Technology 28, 41-45.
49. Hickey, P.J., Beckelheimer, C.E. and Parrow, T. (1993) Microbiological tests for equipment, containers, water and air. In: Marshall, R.T. (ed.) Standard Methods for the Examination of Dairy Products, pp. 397-412. American Public Health Association, Washington, DC.
50. Hiddink, J. (1995 In: Water Supply, Sources, Quality and Water Treatment in the Dairy Industry, Bulletin 308, pp. 16-32. International Dairy Federation, Brussels.
51. Holah, J.T. (2002) Foodborne pathogens: hazards, risk analysis and control. In: Blackburn, C. de W. and McClure, PJ. (eds.) Hygienic Plant Design and Sanitation, pp. 145-148. Woodhead, Cambridge.
52. Holah, J.T. (2003) Cleaning and disinfection. In: Lelieveld, H.L.M., Mostert, M.A., Holah, J. and White, B. (eds.) Hygiene in Food Processing, pp. 235-278. Woodhead, Cambridge.
53. Homleid, J.P. (1997) Spray-disinfection in the dairy industry. Meieriposten 86, 111-112.
54. Hood, S.K. and Zottola, E.A. (1995) Biofilms in food processing. Food Control 6, 9-18.
55. IDF (1979) Design and Use of CIP Systems in the Dairy Industry, Document No. 117. International Dairy Federation, Brussels.
56. IDF (1980) General Code of Hygiene Practice for the Dairy Industry, Document No. 123. International Dairy Federation, Brussels.
57. IDF (1984) General Code of Hygienic Practice for the Dairy Industry and Advisory Microbiological Criteria for Dried Milk, Edible Rennet Casein and Food Grade Whey Powders. Document No. 178, International Dairy Federation, Brussels.
58. IDF (1985) Surface Finishes of Stainless Steels/New Stainless Steels. Document No. 189, International Dairy Federation, Brussels.
59. IDF (1987a) Hygiene Design of Dairy Processing Equipment. Document No. 218, International Dairy Federation, Brussels.
60. IDF (1987b) Hygiene Conditions-General Guide on Sampling and Inspection Procedures, Standard 121A: 1987. International Dairy Federation, Brussels, Belgium.
61. IDF (1991) IDF Recommendations for the Hygienic Manufacture of Spray-Dried Milk Powders, Document No. 267. International Dairy Federation, Brussels.
62. IDF (1992) Hygienic Management in Dairy Plants, Document No. 276. International Dairy Federation, Brussels.
63. IDF (1994) Recommendations for the Hygienic Manufacture of Milk and Milk Based Products, Document No. 292. International Dairy Federation, Brussels.
64. IDF (1996) Codex Standards in the Context of World Trade Agreements/IDF General Recommendations for the Hygienic Design of Dairy Equipment, Document No. 310, pp. 26-31. International Dairy Federation, Brussels.
65. IDF (1997a) IDF Guidelines for Hygienic Design and Maintenance of Dairy Buildings and Services, Bulletin 324. International Dairy Federation, Brussels, Belgium.
66. IDF (1997b) Implications of Microfiltration on Hygiene and Identity of Dairy Products/ Genetic Manipulations of Dairy Cultures, Document No. 320, pp. 9-40. International Dairy Federation, Brussels.
67. IDF (2000) Hygienic Design of Storage Tanks, Bulletin 358, pp. 49-53. International Dairy Federation, Brussels.
68. IDF (2004) Dairy Plant-Hygienic Conditions-General Guidance on Inspection and Sampling Procedures, Standard 121:2004/ISO 8086. International Dairy Federation, Brussels.
69. IDF/FAO (2004) Guide to Good Dairy Farming Practice, pp. 1-2. Joint Publication of the International Dairy Federation and the Food and Agriculture Organization of the United Nations, Rome.
70. Jay, J.M. (1992) Modern Food Microbiology, 4th edn., Von Nostrand Reinhold, New York.
71. Jennings, W.G. (1965) Theory and practice of hard-surface cleaning. Advances in Food Research 14, 325-459.
72. Jeong, D.K. and Frank, J.F. (1994) Growth of Listeria monocytogenes at 10°C in biofilms with microorganisms isolated from meat and dairy processing environments. Journal of Food Protection 57, 576-586.
73. Jervis, D.I. (1992) Hygiene in milk product manufacture. In: Early, R. (ed.) The Technology of Dairy Products, pp. 272-299. Blackie, Glasgow.
74. Jervis, D. (2002) Application of process control. In: Robinson, R.K. (ed.) Dairy Microbiology Handbook, 3rd edn., pp. 593-654. John Wiley, New York.
75. Joseph, B., Otta, S.K., Karunasagar, I. and Karunasagar, I. (2001) Biofilm formation by Salmonella spp. on food contact surfaces and their sensitivity to sanitizers. International Journal of Food Microbiology 64, 367-372.
76. Julien, C., Bénézech, T., Carpentier, B., Lebret, V. and Faille, C. (2002) Identification of surface characteristics relevant to the hygienic status of stainless steel for the food industry. Journal of Food Engineering 56, 77-87.
77. Kang, Y-J. and Frank, J.F. (1989a) Evaluation of air samplers for recovery of biological aerosols in dairy processing plants. Journal of Food Protection 52, 665-659.
78. Kang, Y-J. and Frank, J.F. (1989b) Biological aerosols: a review of airborne contamination and its measurement in dairy processing plants. Journal of Food Protection 52, 512-524.
79. Kang, Y-J. and Frank, J.F. (1990) Characteristics of biological aerosols in dairy processing plants. Journal of Dairy Science 73, 621-626.
80. Kelly, M. (2006) Insect unfriendly packaging design. International Food Hygiene 17, 5-6.
81. Kessler, H.G. (1981) Food Engineering and Dairy Technology. Verlag A. Kessler, Freising, Germany.
82. Kosikowski, F.V. and Mistry, V.V. (1997) Cheese and Fermented Milk Foods, Vol. 2, 3rd edn, pp. 46, 308. F.V. Kosikowski, L.L.C., Westport, CT.
83. Koutzayiotis, C. (1992) Bacterial biofilms in milk pipelines. South African Journal of Dairy Science 24, 19-22.
84. Koutzayiotis, C., Mostert, J.F., Jooste, P.J. and McDonald, J.J. (1992) Growth and activity of Flavobacterium at solid-liquid interfaces. In: Jooste, PJ. (ed.) Advances in the Taxonomy and Significance of Flavobacterium, Cytophaga and Related Bacteria, pp. 103-109. University Press, University of the Orange Free State, Bloemfontein, South Africa.
85. Kumar, C.G. and Anand, S.K. (1998) Significance of microbial biofilms in the food industry: a review. International Journal of Food Microbiology, 42, 9-27.
86. Lehner, A., Riedel, K., Eberl, L., Breeuwer, P., Diep, B. and Stephan, R. (2005) Biofilm formation, extracellular polysaccharide production, and cell-to-cell signalling in various Enterobacter sakazakii strains: aspects promoting environmental persistence. Journal of Food Protection 68, 2287-2294.
87. Lelieveld, H.L.M. (2003a) Introduction. In: Lelieveld, H.L.M., Mostert, M.A., Holah, J. and White, B. (eds) Hygiene in Food Processing, pp. 1-2. Woodhead, Cambridge.
88. Lelieveld, H.L.M. (2003b) Sources of contamination. In: Lelieveld, H.L.M., Mostert, M.A., Holah, J. and White, B. (eds) Hygiene in Food Processing, pp. 61-75. Woodhead, Cambridge.
89. Lelieveld, H.L.M., Mostert, M.A. and Curiel, G.J. (2003) Hygiene equipment design. In: Lelieveld, H.L.M., Mostert, M.A., Holah, J. and White, B. (eds.) Hygiene in Food Processing, pp. 122-166. Woodhead, Cambridge.
90. Lewis, K. (2001) Riddle of biofilm resistance. Antimicrobial Agents and Chemotherapy 45, 999-1007.
91. Lindsay, D. and Von Holy, A. (1999) Different responses of planktonic and attached Bacillus subtilis and Pseudomonas fluorescens to sanitizer treatment. Journal of Food Protection, 62, 368-379.
92. Lindsay, D. and Von Holy, A. (2006) What food safety professionals should know about bacterial biofilms. British Food Journal 108, 27-37.
93. Lück, H. and Gavron, H. (1990) Quality control in the dairy industry. In: Robinson, R.K. (ed.) Dairy Microbiology-The Microbiology of Milk Products, Vol. 2, 2nd edn, pp. 345-392. Elsevier Applied Science, London.
94. Lundén, J.M., Miettinen, M.K., Autio, T.J. and Korkeala, H.J. (2000) Persistent Listeria monocytogenes strains show enhancement adherence to food contact surface after short time contact time. Journal of Food Protection, 63, 1204-1207.
95. Majoor, F.A. (2003) Cleaning in place. In: Lelieveld, H.L.M., Mostert, M.A., Holah, J. and White, B. (eds.) Hygiene in Food Processing, pp. 197-219. Woodhead, Cambridge.
96. Marriott, N. (1999) Principles of Food Sanitation, 4th edn. Aspen, Gaithersburg, MD.
97. Mattila-Sandholm, T. and Wirtanen, G. (1992) Biofilm formation in the industry. A review. Food Reviews International 8, 573-603.
98. Mettler, E. and Carpentier, B. (1998) Variations over time of microbial load and physicochemical properties of floor materials after cleaning in food industry premises. Journal of Food Protection 61, 57-65.
99. Meyer, B. (2003) Approaches to prevention, removal and killing of biofilms. International Biodeterioration and Biodegradation 51, 249-253.
100. Mittelman, M.W. (1998) Structure and functional characteristics of bacterial biofilms in fluid processing operations. Journal of Dairy Science 81, 2760-2764.
101. Mostert, J.F. and Jooste, P.J. (2002) Quality control in the dairy industry. In: Robinson, R.K. (ed.) Dairy Microbiology Handbook, 3rd edn., John Wiley, New York, pp. 655-736.
102. Nelson, J. (1990) Where are Listeria likely to be found in dairy plants? Dairy Food and Environmental Sanitation 10, 344-345.
103. Neve, H., Berger, A. and Heller, K.J. (1995) A method for detecting and enumerating airborne virulent bacteriophage of dairy starter cultures. Kieler Milchwirtschaftliche Forschungsberichte 47, 193-207.
104. Noterman, S. (1994) The significance of biofouling to the food industry. Journal of Food Technology 48, 13-14.
105. Oosthuizen, M.C., Steyn, B., Lindsay, D., Brözel, V.S. and Von Holy, A. (2001) Novel method for the proteomic investigation of a dairy-associated Bacillus cereus biofilm. FEMS Microbiology Letters 194, 47-51.
106. Orth, R. (1998) The importance of disinfection for the hygiene in the dairy and beverage production. International Biodeterioration and Biodegradation 41, 201-208.
107. Parsek, M.R. and Fuqua, C. (2004) Biofilms 2003: emerging themes and challenges in studies of surface-associated microbial life. Journal of Bacteriology 186, 4427-4440.
108. Parsek, M.R. and Greenberg, E.P. (2005) Sociomicrobiology: the connections between quorum sensing and biofilms. Trends in Microbiology 13, 27-33.
109. Potthoff, A., Serve, W. and Macharis, P. (1997) The cleaning revolution. Dairy Industries International 62, 25, 27, 29.
110. Reinemann, D.J., Wolters, G., Billon, P., Lind, O. and Rasmussen, M.D. (2003) Review of practices for cleaning and sanitation of milking machines. In: IDF Bulletin, 381, pp. 3-11. International Dairy Federation, Brussels.
111. Robinson, R.K. and Tamime A.Y. (2002) Maintaining a clean working environment. In: Robinson, R.K. (ed.) Dairy Microbiology Handbook, 3rd edn, pp. 561-591. John Wiley, New York.
112. Romney, A.J.D. (Ed.), (1990 In: CIP: Cleaning in Place, 2nd edn. Society of Dairy Technology, Huntingdon, UK.
113. Russell, P. (1997) Monitoring hygiene. Milk Industries International 99, 25-29.
114. Shah, B.P., Shah, U.S. and Siripurapu, S.C.B. (1996) Air-borne contaminants in dairy plants-a review. Indian Dairyman 48, 19-21.
115. Shah, B.P., Shah, U.S. and Siripurapu, S.C.B. (1997) ULPA filter for contamination free air in dairy plant. Indian Dairyman 49, 23-27.
116. Shapton, D. and Shapton, N. (1991) Principles and Practices for the Safe Processing of Foods. Woodhead, Cambridge.
117. Steward, P. S., Roe, F., Rayner, J., Elkins, J.G., Lewandowski, Z., Ochsner, U.A. and Hassett, D.J. (2000) Effect of catalase on hydrogen peroxide penetration into Pseudomonas aeruginosa biofilms. Applied and Environmental Microbiology 66, 863-868.
118. Stoodley, P., De Beer, D. and Lewandowski, Z. (1994) Liquid flow in biofilm systems. Applied and Environmental Microbiology 60, 2711-2716.
119. Swart, M. (1995) The presence and importance of microorganisms in alkaline detergents used in the dairy industry. MSc thesis, Potchefstroom University for CHE, Potchefstroom, South Africa.
120. Swartling, P. (1959) The influence of the use of detergents and sanitizers on the farm with regard to the quality of milk and milk products. Dairy Science Abstracts 21, 1-10.
121. Tamime, A. Y. and Robinson, R.K. (1999) Yoghurt Science and Technology, 2nd edn. Woodhead, Cambridge.
122. Tamminga, S.K. and Kampelmacher, E.H. (1977) Bacteriology of dairy products. Zentralblatt fur Bakteriologie Mikrobiologie und Hygiene I Abteilung Originale B165, 423-426.
123. Timperley, D. and Lawson, G. (1980) Test rigs for evaluation of hygiene in plant design. In: Jowitt, R. (ed.) Hygienic Design of Operation of Food Plant, pp. 171-179, Ellis Horwood, Chichester, UK.
124. Timperley, D.A., Hasting, A.M.P. and de Goederen, G. (1994) Developments in the cleaning of dairy sterilization plant. Journal of the Society of Dairy Technology 47, 44-50.
125. Vinson, H.G. (1990) Hygienic design of a dairy. Journal of the Society of Dairy Technology 43, 39-41.
126. Wainess, H. (1982) Hygienic design and construction of equipment used in dairy plants. In: IDF Bulletin, Doc. No. 153, pp. 3-10. International Dairy Federation, Brussels, Belgium.
127. Wainess, H. (1995) Design, construction and operation of packaging equipment. In: Technical Guide for the Packaging of Milk and Milk Products, 3rd edn., Bulletin 300, pp. 40-46, 47-51. International Dairy Federation, Brussels.
128. WHO (1994) Environmental Health Criteria 160. World Health Organization, Vammala, Switzerland.
129. WHO (1996) Guidelines for Drinking-Water Quality. World Health Organization, Geneva.
130. WHO (2005) Water Drinking Guidelines. World Health Organization, Geneva. http://w3.whosea.org/techinfo/water.htm (accessed 2 December 2005).
131. Wierenga, G. and Holah, J.T. (2003) Hygienic plant design. In: Lelieveld, H.L.M., Mostert, M.A., Holah, J. and White, B. (eds.) Hygiene in Food Processing, pp. 76-105. Woodhead, Cambridge.
132. Wirtanen, G., Salo, S., Maukonen, J., Bredholt, S. and Mattila-Sandholm, T. (1997) Sanitation in Dairies, VTT Publication No. 309. Technical Research Center, Espoo, Finland.
133. Witter, L.D. (1961) Psychrophilic bacteria-a review. Journal of Dairy Science 44, 983-1015.
134. Wong, A.C.L. and Cerf, O. (1995 In: Biofilms: Implications for Hygiene Monitoring of Dairy Plant Surfaces. Bulletin 302, pp. 40-44. International Dairy Federation, Belgium.