Thermal processing remains the most important method of food preservation in use today, and the scale of the industry is immense. The large scale of these production operations makes it more important than ever that the process is performed perfectly every time: failure will lead to product deterioration and loss of sales at best, and at worst to serious illness or death. This volume isa definitive modern-day reference for all those involved in thermal processing. It covers all of the essential information regarding the preservation of food products by heat. It includes all types of food product, from those high inacid and given a mild heat process to the low-acid sterilised foods that require a full botulinum cook. Different chapters deal with the manufacturing steps from raw material microbiology, through various processing regimes, validation methods, packaging, incubation testing and spoilage incidents. The authors have extensive knowledge of heat preservation covering all parts of the world and represent organisations with formidable reputations in this field INDICE: "1. Microbiology for heat processed foods.This introductory chapter contains information on the types and numbers of microorganisms that can be expected in raw materials. This leads to a value for the initial number of target microorganisms for which the heat process aims to reduce to a commerciallyacceptable number. Also included are the fundamentals of microorganism death by moist heat. Definitions of commercial sterility are given. Also included are the nature of spores, the mechanism of death, role of thermophiles and emerging pathogens..2. Hurdles to microbial growth .A number of hurdles to microbial growth are described, including water activity, pH, storage temperature, andpreservatives such as salt and sugar. These can be used alone or in combination..3. Low acid canned foods.This group of foods does not contain any preservation hurdles to microorganism growth and relies solely on the heat process to control microorganism numbers. The history of this sector is given and of the evolution of the F03 process. Post-process spoilage is the main category of canned food spoilage for low acid foods. It includes pre-processing spoilage, vulnerable products (e.g. mushrooms), and control of initial counts / loads..4. Acid and high acid foods.Includes foods naturally high in acid, from lemon juice and fruits through to tomato products. Target microorganisms and therefore the recommended process times and temperatures are dependent on pH. Hot fill is one of the processing technologies suitable for high acid products..5. Acidified products.These groups of products have acids added in the product formulation so that mesophilic strains of Clostridium botulinum cannot grow and a milder pasteurisation process given. Target microorganisms and therefore the recommended process times and temperatures are dependent on pH. Examples of these foods are many and include pickles, yoghurts and cook-in-sauces..6. Heat preserved chilled foods.This is a growing sector world-wide and includes sous-vide products. It includes two main groups of foods together with many niche products. The two main groups target either Listeria monocytogenes or psychrotrophicstrains of Clostridium botulinum because of the ability of these organisms togrow in chilled conditions. Ready-to-eat oven cooked meat, fish and poultry products are also an important category within Europe. Factory designs for these products are often based on a low and high risk area, with the heat process taking place in low risk and packaging in high risk. Further products include high quality foods and drinks such as acid tomato-based sauces, fruit juices and smoothies..7. Processing Methods.Batch and continuous retorts: The main types of batch retort are described, for example steam, steam-air, water immersion, raining and sprayed water; including hydrostatic and reel & spiral cooker-cooler systems. Strengths, weaknesses and operating conditions are given, together with discussions about designs to avoid cold spots and corrosion issues. Continuous and alternative processing types: Included in this chapter are processes that use heat exchangers and pressure vessels to achieve the time and temperature combination. Examples of equipment include heat exchangers based on plates, tube or scraped surface, or the alternative technologies such as ohmic and microwave. Food products are heated (pasteurised or sterilised) prior to filling into the package, which can either be an aseptic fill for ambient shelflife or a clean fill for chilled shelf life.8. Cooking and process optimisation .Choice of process times and temperatures are often based on cooking criteria such as colour or texture. This chapter addresses the challenges of maximising a specific quality attribute without reducing the thermal processing effect on microbial reduction. Examples are given on the different quality parameters appropriate to heat preserved foods and how these can be mathematically analysed. Examples are then presented to illustrate how process times and temperatures can be adjusted so that maximum quantities of a nutrient such as vitaminB are retained..9. Measurement and validation of thermal processes.Techniquesfor measuring the thermal processing efficacy are described together with theprocess calculation methods used to establish safe times and temperatures. Measurement techniques include temperature sensors of various types, microbiological methods using count reduction, and biochemical time-temperature integrators. Differences in the techniques required for batch (in-pack) and continuous (in-flow) heat processes are described. Some of these calculation techniques, e.g. Formula and numerical methods, are required to analyse the effect of foodsafety of a process deviation. Establishment of CCPs within a HACCP system are given. Also included are the frequency of testing or retesting and reasons for redoing validation studies..10. Cooling and Cannery water treatment .Discussions about the importance of cooling, with regard to quality and thermophilicspoilage. Information about different methods of cannery water treatment..11.Handling Processing Deviations .How to assess weather a process deviation hasmade a critical impact on the commercial sterility or safety of a product. Methods for calculating, including ways to estimate, should software not be available.12. Packaging options .Packaging formats are described that enable heat preserved foods to remain in a suitable condition for sale. These include metal cans, glass jars and bottles, plastic packs such as bowls, trays and pouches. Barrier properties to gases, light and water can limit shelf life. Relative strength of the packaging material is important for retorted packs. Includes materials specifications and integrity of seals..13. Incubation testing .A variety of incubation practices occur in the food industry. This chapter will describe the objectives of incubation together with some recommendations for timesand temperatures that different types of microorganism require. Includes sample size and selection, also interpretation of results...14. Spoilage investigations.Different types of spoilage are described such as pre-process, under-process and leaker spoilage (post-process). Historical data are given for numbersof each type of spoilage type. Examples of spoilage and poisoning incidents are given together with the understanding that resulted from these incidents. Methods to investigate a spoilage incident are given."
- ISBN: 978-1-4051-9058-9
- Editorial: Wiley-Blackwell
- Encuadernacion: Cartoné
- Páginas: 288
- Fecha Publicación: 26/11/2010
- Nº Volúmenes: 1
- Idioma: Inglés