Low acid foods

It is an anaerobic, gram-positive, spore-forming, rod-shaped bacterium that produces neurotoxins (see C16-A005), especially in low-acid foods. The natural reservoir is soil. It is also found in honey. This is a biosafety level 2 agent. 

The purpose of this process is the production of foodstuffs that are shelf stable at ambient temperatures and that have better quality characteristics than the corresponding heat-sterilized products. Radappertization dose of low-acid foods must ensure elimination of the spores of the most resistant bacterial pathogen, C. botulinum. The dose selected for the purpose is around 50 kGy, 12 times of the Z>io value. As the product is intended to be shelf-stable at ambient temperature, while autolytic enzymes have high radiation resist-... 

Low acid foods have a pH > 4.5, require steriliz.aliun at temperatures above 100 C. and thus require treatment in pressure vessels. Heat preservation processes above 100 C can he carried out in batch or continuous heat-exchange equipment. 

Thermally Processed Low-Acid Foods Packaged in Hermetically Sealed Containers... 

Acidified foods are defined as "low acid" foods to which acid(s) or acid food(s) are added these foods include, but are not limited to... 

Separations of several cations in mineral water, pond water, or low acid foods... 

CaClj often is added to low acid foods such as com, beans, and peas to prevent them from becoming too mushy when they are cooked. The calcium, being a dication, can associate with carboxyl groups between two cell walls and help hold the cells together, producing a firmness and a better mouth feel. 

You are a chemist in a private analytical laboratory, and your specialty is determining ions in aqueous liquid samples such as mineral waters or pond water and the added ions in low acid foods. You are prepared to handle any of these samples. You have been given one of these by your boss as a quality control sample. 

A strong acid cation exchange resin is converted to the H form. This then is used to remove the cations from a liquid sample such as mineral water, pond water, or the juices from low acid foods and exchange them with H. An aliquot of the sample containing H" will be titrated with standard base to determine the total amount of ions present. A second aliquot will be titrated with EDTA to determine the total calcium and magnesium ions present, and a third aliquot will be used to determine magnesium, again with an EDTA titration. 

Gavin and Weddig, 1995). Therefore, a pH of 4.6 has been selected as the dividing line between acid and low-acid foods. 

Rose, D., 1985, Guidelines for the processing and aseptic packaging of low acid foods. Part 1. Principles of design installation and commissioning. Campden Food Preservation Research Association. Chipping Campden. 

Virtually all of the six-carbon aldehydes and alcohols found in freshly cooked pumpkin have been lost. Furfural has increased significantly and 2-methyl tetra-hydrofuran-3-one has appeared. These changes are likely due to the severe thermal processing canned pumpkins must receive. Pumpkins are a low acid food which heat primarily by conduction and as such require extended processing times at 250°F or higher. Furfural is a well known constituent of thermally decomposed carbohydrates, and the furanone as well as the furyl-ketone have been reported in numerous cooked food products (10). 2-Methyl butanal and iso valeraldehyde are also craranon constituents of pro-... 

For asceptic packaging, both the food product and the container are sterilized separately and then brought together in a sterile environment. Both low-acid foods, like yogurt and soup, and high-acid foods, such as juices and drinks, are packaged by this method. 

Hot-fill pouches are used for both low- and high-acid applications. Heinz Company s form-fill seal Pouch Pack, which is claimed to give a shelf life of one year, has a web of 3-mil LLDPE, ethylene-acrylic acid copolymer, 35-gauge foil, ethylene-acrylic acid copolymer, and biaxially oriented nylon, from inside outward. The Pouch Pack system from Du Pont offers pouches of sizes 4 oz to 1.5 L to fill a range of high-and low-acid food applications at various temperatures, including fruit toppings at 80°C. 

Lemons, with a pH of about 2.0, are extremely sour. The acid responsible for this sourness, as well as that of limes, oranges, and grapefruit, is citric acid. Citrus fruits, like many acidic foods, are resistant to spoilage because many microorganisms cannot survive the low pH environment. Many low-acid foods can be... 

Dascription and Prinsipla Properlv prepared foods are placed in the gto or can oontaneis and seabf. Then depembig upon the type of food (pn-marily the acidity pH l. the cans or bonles are heated to a known temperature and then held at that lemperature lor a specified time. Low acid foods such as meats and vegetables are heated to 240 td 26S f tffS" re 2S" 0 while acidic toads such as Irons are heated to aboui 212 F 1 00 >C. ... 

Clostridium Botulinum. This potentially deadly microorganism can cause a disease called botulism that can affect the central nervous system. The bacteria is anaerobic, meaning it can grow in low-oxygen conditions, such as in an improperly sealed can or jar, and particularly in low-acid foods, such as canned green beans. Botulism can cause nerve and brain damage, paralysis, and even death in those with weakened or compromised immune systems. 

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