Rosalee Brown

In the modern world, food processing is a reality and the quest is to find safer methods to produce food of higher quality while retaining their value.

Most fruits and many vegetables are high in sugars and organic acids which can act as a form of preservative, as they provide an acid medium in which some bacteria cannot survive. This medium however is a haven for other types of microorganisms such as mould, yeast and acidophyllic bacteria, which cause food spoilage. Some of this spoilage can result in great losses to the manufacturer, by affecting flavour, colour and clarity of the juice, while others can lead to serious illness if the contaminated juices are consumed.

Pasteurisation

Pasteurisation is a method used to reduce these microorganisms to a safe level, therefore increasing the shelf life of the product if maintained at standard refrigerated temperatures after pasteurisation. The products are quickly taken to a high temperature for a short time then quickly cooled to refrigerated temperature. The maintenance of this refrigerated temperature is crucial to retard spoilage. Many of these microorganisms are present naturally on the fruits, but the load can be increased by poor processing methods, which include contamination by the tools used in processing.

Fermentation

Fermentation, which can be evident by swollen juice containers, is the result of the gases and other metabolites given off by the enzymatic reactions of these microorganisms. It results naturally as time increases after harvesting of the fruit/vegetable, but can be accelerated by the right temperature.

These fermented juices result in 'off' flavours, colours and appearance in the juice. These organisms which cause fermentation will not cause illness in the healthy adult, as many are the same organisms used in food processing. For example, yeast such as saccharomyces cerevisiae, is used in bread making, bacteria such as Leuconoctoc spp. is used to impart flavour to cheddar cheese, Penicillium roqueforti is used in blue cheese and lactobacillus plantarum and Lactobacillus brevis are used in cucumber pickles. However, many of these fermenting microorganisms can be potentially dangerous to the young, infants, old and those with weakened immune systems.

Hazard analysis

Since 2002 in the United States, juice manufacturers have had to adhere to the Hazard Analysis Critical Control Point (HACCP) method for juice processing. This is a systems method, which identifies hazards and ensures that measures are in place in the chain from the beginning of processing to delivery to eliminate these hazards.

Juices also carry a best by and expiry date, indicating optimum consumption periods. These dates are only applicable however if all the conditions for safety, most important of which is temperature, are maintained. Many consumers can attest to the fact that they purchase juices long before this expiry date and fermentation has already started. This happens quite often because there was a breach at some point in the temperature chain or damage to the packaging.

Again, consumers, you need to force the processors and retail chains to adhere to these standards by refusing to accept substandard products. Often consumers purchase fermented juices and just discard it without complaining to the retailer.

We must indicate, no matter how often it happens. Sometimes, it may seem more costly to return the product, however you can make contact by telephone and then return the product when it is convenient. This is one way to ensure improved quality in the products offered for sale.

Rosalee M. Brown is a registered dietitian/nutritionist who operates Integrated Nutrition and Health Services; email: yourhealth@gleanerjm.com.