eChapters

Introduction

In a research laboratory, we frequently need weigh chemicals and prepare different solutions of varying strength, as per the requirements. Accuracy in weighing and preparation of solution, with respect to weight/volume and strength, determines the success of experiment. In turn, the accuracy depends on weighing of solid chemical and/or measuring the volume of liquid chemical/making up the volume. In this Chapter, weighing of chemicals using appropriate weighing balance, preparation of solutions of different strength, their dilution, and precautions while preparing will be discuss in brief.

Weighing of Chemical

The primary method to determine the amount of chemicals to be used is weighing the chemical by using a balance.

In general, there are two types of balances to weigh chemicals in a laboratory:

1. Standard laboratory balance

2. Analytical balance

Standard Laboratory Balance

Generally, a standard laboratory balance is used for weighing a chemical when an error of ±0.02 g is acceptable. It is also used for pre-weighing, where approximate mass needs to be determined. Precise mass of the chemical is then determined using an analytical balance. Following are the steps in using a weighing balance in a laboratory.

When certain disease-causing bacteria or pathogens contaminate food, they can cause foodborne illness, often called “food poisoning”. Foods that are contaminated may not look, taste or smell any different from foods that are safe to eat. Salmonella, Campylobacter, Listeria and Escherichia coli are common bacteria causing foodborne illness. Some foodborne illnesses are mild where most people get better within a few days, but illness can sometimes be more severe and fatal. Bacillus cereus can form heat resistant spores. On cooking the food with these spores the heat resistant toxin is left at room temperature. Reheating or lightly cooking the food does not destroy these toxins. Most types of foodborne illnesses cause symptoms like nausea, vomiting, watery diarrhea, abdominal pain and cramps. Fever and/or the presence of blood or mucus in the stool are signs of bacterial infection that may require a medical consultation. Proper food handling is vital to prevent most foodborne illnesses and diseases. WHO has given keys towards safer food which should be followed. Unsafe food containing harmful bacteria, viruses, parasites or chemical substances, causes more than 200 diseases which range from diarrhoea to cancers. Foodborne and waterborne diarrhoeal diseases kill around 2 million people worldwide annually, including many children. A single foodborne bacterium can grow into more than two million bacteria in just seven hours under the right conditions. Foodborne pathogen called Listeria sp. can survive and sometimes grow on foods being stored in the refrigerator. Hepatitis A virus can cause long-lasting liver disease and spreads typically through raw or undercooked seafood or contaminated raw produce. It is estimated that more than 250 million people worldwide suffer food allergies. The boiling temperature (smoke point) of cooking oil is above 200 °C. The boiling point of water is 100 °C.

According to the World Health Day (WHO,2015) food contamination happens when food are corrupted with another substance. It can happen during the process of production, transportation, packaging, storage, sales and cooking process. The contamination can be physical, chemical and biological. Faulde et al., (2013) studied the infection caused to patients by mothfly

It is a discipline of science that describes handling, preparation and storage of food that can prevent food-borne diseases. When there are two or more cases of a similar illness from the ingestion of the same common food it is known as a food-borne disease outbreak (FSN, 2018). In order to avoid potential health hazards, food safety is very important. This needs safety between industry, market and the consumer. For food safety the labelling on food material is vital. This includes the origin of food, steps taken for food hygiene, food additives, pesticide residues, policies on biotechnology, food guidelines for the management of governmental import, export inspection and certification systems for foods. The food should be safe in the market with safe preparation and delivery of the food for the consumer. Foegeding et al., (1996) have done an assessment of risk factors with food borne pathogens.Warnock et al., (2007) have reported intervention to food safety.

When pathogens are in the food they may be transmitted to the consumer. It may result in an illness or death of the person or other animals. The pathogens include bacteria, viruses, molds and fungus. These multiply in the food medium. Joon et al., (2012) have found pathogenic bacteria in meat products of Korea. The developed countries have high intricate standards for the preparation of food; however, in the developing countries there are less standards and enforcement of the standards which are followed. Apart from food another major source of infection is water, which is very critical in spreading many diseases. It is possible to prevent food poisoning if good water is used for all purposes. However, it becomes difficult as in the food supply chain a large number of persons are involved apart from the fact that pathogens can be introduced into foods no matter how much precautions are taken. Cowden (2000) has studied the notification on food poisoning to improve health. Frenkel et al., (2015) studied the amount of wastes from food processing industries.

A process control system that identifies the hazardous points in the food production process is known as HACCP (Hazard Analysis Critical Control Point). It puts into place many stringent actions to prevent any hazards from occurring. In any food process if there is strict monitoring and controlling steps, the chances for hazards are minimum. Today, HACCP is an integral part of modern food industry that identifies and controls the major food risks. These are like microbiological, chemical and physical contaminants. These can also be practiced at home scale by checking proper storage, handling, cooking and cleaning procedures. These steps have resulted in industries taking greater responsibility for and controlling the food safety risk factors. This helps in better consumer protection, agriculture, the food processing industries and promotes domestic and international food trade.

The temperature of food storage is important. Below 4⁰C the food pathogens do not grow. Above 60⁰C some colonies begin to die. However, almost all die at 71⁰C. How hot is the food served is important for food safety. The size of the piece is important to how quickly it will cook all the way through. The smaller the piece the faster it will cook. Large or thicker pieces take a longer time to be cooked. Otherwise cooking for a longer time is better so that pathogenic microorganisms do not grow. In case of a thicker piece the color must be checked inside to outside after cooking which should be consistent. If the meat has the bone, check the color/temperature closest to the bone in the thickest part. In case of meat the contamination usually gets introduced while butchering and the practices used. The street food on a cart is perhaps the most contaminated as it has some level of bacteria in it. The meat in the decorated malls also has pathogenic bacteria. The environment plays a very pivotal role which can recontaminate the food even after proper cooking. The amount of harmful pathogens keeps growing in number with the passage of time. Fresh from the grill is the best, an hour or two is not ideal, half a day or overnight could make a person sick. Due to the reason that consumers do not know the time and temperature of cooking it is important to eat food which is freshly prepared.

Apart from the job content and specialization, the conditions or the atmosphere in which employees work is critical to their productivity. Work environment includes the tools and equipment provided to perform the job, the atmosphere at the work place, worker motivation etc.

Tools and Equipments

The quality of tools and equipment provided to a worker has a profound effect on the worker’s contribution to his job. A poorly designed tool can cause excessive physical burden on the worker and may result in fatigue. A faulty computer monitor can cause severe eyestrain, which might affect productivity in an office environment. Hence, tools and equipment should be appropriate for the production task. The design should consider ergonomic factors like grasping pressure, size, weight, ease of use etc. when designed properly, tools enable users to work efficiently, resulting in higher productivity. The equipment installed should be able to meet the capacity requirements of the job, have safety features and be easy to use. The use of the right tools and equipment can improve productivity in an organization substantially.

Yeasts

Yeasts are non filamentous, unicellular fungi that are typically spherical or oval. Like molds, yeasts are widely distributed in nature; they are frequently found as a white powdery coating on fruits and leaves.