Show description

Heat treatment Inadequate processing may result in spoilage by thermoduric and sometimes mesophilic spore-forming bacteria. Though rare, in the extreme it can lead to spoilage by vegetative bacteria. ). In the former, the ends of the container remain flat (so-called ‘flat-sour spoilage’), and in the latter the can may swell and eventually burst. Spoilage by mesophilic Clostridium spp. may be fermentative, with the production of acid and gas, or putrefactive. In the latter, the anaerobic decomposition of proteins into peptides and amino acids causes the production of foul odours due to hydrogen sulphide, ammonia, amines and other strong-smelling products.

7). , on environmental routine and investigative screening. 10 ᭜ Salmonella spp. g. 6 ᭜ Dairy Products (Hygiene) Regulations (1995) [13] Microbiological criteria for cheese Dairy Products (Hygiene) Regulations (1995) [13] The following criteria are applicable to the manufactured product on removal from the processing establishment. Product Organism Standard Cheese other than hard cheese Listeria monocytogenes Absent in 25 g, n = 5, c = 0 Hard cheese All products Salmonella spp. (from 5 x 5 g samples) Absent in 1 g, n = 5, c = 0 Absent in 25 g, n = 5, c = 0 Cheese made from raw or Staphylococcus aureus m = 103, M = 104, n = 5, c = 2 thermised milk m = 102, M = 103, n = 5, c = 2 Soft cheese (made from heat treated milk) m = 10, M = 102, n = 5, c = 2 Fresh cheese Cheese made from raw or Escherichia coli m = 104, M = 105, n = 5, c = 2 thermised milk m = 102, M = 103, n = 5, c = 2 Soft cheese (made from heat treated milk) Indicator organisms — guidelines: Soft cheese (made from heat Coliforms (30oC) m = 104, M = 105, n = 5, c = 2 treated milk) n, the number of sample units; m, the threshold value for the number of bacteria (satisfactory if not exceeded); M, the maximum value for the number of bacteria (unsatisfactory if exceeded); c, the number of sample units where the bacterial count may be between m and M.

5 or less) to make such treatment unnecessary. A modified methylene blue reduction test has been used as a crude indication of the hygienic quality of ice-cream; products that are coloured or contain additives such as fruit juices and nuts are unsuitable for the test. A combination of colony count and coliform count is commonly used in industrial quality control. Microbiological criteria for frozen milk-based products, including ice-cream, sampled at the processing establishment, are contained in the Milk and Milk- 40 Section three based Products Directive 92/46/EEC [12] and the Dairy Products (Hygiene) Regulations (1995) [13].