生物防腐剂在乳制品中的应用

综述了几种生物防腐剂的特性和抑菌机理以及在乳制品中的应用和一些最新的研究成果。     

ADVANCES IN THE CHEMISTRY OF MILK AND DAIRY PRODUCTS

Present knowledge of the chemistry of the fat and proteins of milk is reviewed briefly in relation to properties of milk and dairy products of commercial importance. The dietary factors affecting milk composition and the chemical and physical changes during storage or processing are also discussed.     

ADVANCES IN THE MICROBIOLOGY OF MILK AND DAIRY PRODUCTS

The techniques of microbiology from the seventeenth century up to the present time are reviewed and the problems of disease in dairy herds with its effect on raw milk supplies assessed. Progress in the cleaning of milk vessels and sterilization is detailed and the history of pasteurization with its affect on the keeping quality of milk is shown. The introduction of starters in cheese manufacture during the last century is described and the important advances made are stressed.     

IN DAIRY PRODUCTS

The paper deals with the latest equipment available for the detection of both ferrous and non-ferrous metals in dairy products. The basic principle of the equipment is described and deals with both the metal detector, the conveyor and its associated automatic rejection system. A detection equipment which can sense the presence of ferrous metal in foil-wrapped goods is also described. A summary of the activity on the development of a foreign body detection using 'soft' X-rays is also dealt with, and the performance of the system on foreign bodies such as metal, glass and stone is quantified.     

TRENDS IN SUPPLY AND DEMAND FOR MILK AND DAIRY PRODUCTS IN THE UK

The paper examines the changes in yields and dairy cow numbers in recent years and considers the likely economic prospects for investment in modern dairy units. With full Community prices applied in the UK at a realistic rate of exchange, dairying would be very profitable. In spite of the setback between 1973 and 1975 the milk output objective of the Government's White Paper 'Food from Our Own Resources' should be reached in the first half of the 1980s. Liquid milk consumption will be fairly stable in the future, but with the higher prices under the Community régime the butter market will contract. A modest increase in cheese consumption will continue. Higher milk production in the UK and a reduced market will increase self-sufficiency. In spite of the European surplus in the dairy sector the competitive strength of the UK industry at Community prices is substantial and it is economically right for it to expand.     

PREVALENCE OF ANTIMICROBIAL RESIDUES IN MILK AND DAIRY PRODUCTS IN THE STATE OF KUWAIT

ABSTRACT

Approximately, 1,000 locally produced and imported milk and dairy product samples were collected at different seasonal periods from different farms and retail outlets in Kuwait, and screened for the presence of four antimicrobial residues (beta‐lactams, tetracyclines sulfonamides and chloramphenicol) using Charm II system. Results indicated that 29.1% of the analyzed local fresh milk samples were above the maximum residue level (MRL) for tested residues with tetracycline as predominant residue. The prevalence of antimicrobial residues in imported pasteurized milk samples (5.4%) was higher than that of local pasteurized milk samples (3.4%). No residues were detected in powdered and condensed milk samples imported from the European Union (EU) countries with the exception of tetracyclines. Results also showed that 9.4% of the analyzed imported cheese samples were above the MRL for tested residues, while tested ice cream samples were negative for antimicrobial residues. The significant presence of antimicrobial residues, particularly chloramphenicol, in raw and pasteurized milk, clearly implies the misuse of antimicrobial drugs in animal farms in Kuwait and neighboring countries, and implies the need for stricter regulations on antimicrobial drug usage in the dairy industry.

PRACTICAL APPLICATIONS

This article addresses the generation of a baseline data on the current presence of four antimicrobial residues in locally produced and imported milk and dairy products in the state of Kuwait. The outcome of this study will provide valuable baseline information for local governmental authorities for effective monitoring for the use and misuse of agricultural antimicrobial drugs. Such data will also be important for other Gulf Cooperation Council countries, because such countries share similar farming practices and import comparable foodstuffs.

     

ELECTRIC SENSOR FOR PROMPT MEASUREMENT OF MOISTURE CONTENT IN SOLID FOOD PRODUCTS

Originally designed sensor for electrical measurement of moisture content in comminuted food was presented. Equations were formulated to demonstrate the dependence of tested sample electrical resistance on resistivity (specific resistance) of food as well as the dependence of investigated sample electrical capacitance on permittivity of food. Experiments were carried out to determine moisture content in wheat flour, potato starch, and raw pork loin serving as examples. The results of these measurements were compared with the results obtained using conventional gravimetry. The measurement of moisture content lasted for between 3 to 5 s, and the time used for a sample preparation was not longer than 60 s. An advantage of the designed sensor of moisture content is that the density of the investigated food sample does not affect the measurement results.